Hitachi LR150 50A alternator
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- ecomike
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- Location: Houston Tx
Well they checked out my dead unit. He said the diodes went as we suspected and they said the armature was marginal (the field from the windings was week on their test unit), quoted me apx $130 max to rebuild it if they replace the armature with a rewound one, plus all the other parts.
Takes a week to ship mine off for rewinding which I said no to for now. He was not sure what they were going to do about the armature yet. I told him to do whatever they could do and get it ready for pick up tomorrow afternoon. I also asked him to see if he could find a rebuilt unit, ready to go locally from his sources.
Takes a week to ship mine off for rewinding which I said no to for now. He was not sure what they were going to do about the armature yet. I told him to do whatever they could do and get it ready for pick up tomorrow afternoon. I also asked him to see if he could find a rebuilt unit, ready to go locally from his sources.
Regards,
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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Well I am an EE, so I'll chime in on the SCR (Silicon-Controlled Rectifier). It's basically a diode that has a latching 'on' switch. You can place a voltage across it in its 'off' state and no current flows. Then upon driving a certain amount of currrent into the gate, the device then turns 'on' and remains on until the current through the device is interrupted by some external means. So they are not very useful in DC circuits because once you turn it on, you have to use some other device to turn the circuit off. On AC, however, they will turn off at every zero-crossing of the current waveform, which makes them very useful for power control. A Triac is basically two SCRs back-to-back, and this is really what is used inside most light dimmer switches and small variable-speed motor controllers (aka ceiling fan controls).
This link has a great primer on these devices.
For variable-speed control of a DC electric cooling fan, the easiest thing to do is to use a power resistor to drop the voltage to the motor for a lower speed. If you have two fan motors, you can rig some relays to switch them in series (low fan speed) or parallel (high fan speed) and avoid using a power resistor.
This link has a great primer on these devices.
For variable-speed control of a DC electric cooling fan, the easiest thing to do is to use a power resistor to drop the voltage to the motor for a lower speed. If you have two fan motors, you can rig some relays to switch them in series (low fan speed) or parallel (high fan speed) and avoid using a power resistor.
- asavage
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- ecomike
- Posts: 242
- Joined: 18 years ago
- Location: Houston Tx
Redmondjp,asavage wrote:Good to have my advice vetted. Thanks.redmondjp wrote:For variable-speed control of a DC electric cooling fan, the easiest thing to do is to use a power resistor to drop the voltage to the motor for a lower speed.
Thanks for the feedback.
Assuming one has a 250 watt, 12 volt DC fan, how do we size the wattage requirements for the voltage dropping resistor if we want to drop the voltage to say 10 volts, and how do we calculate the resistors ohms needed to drop it to say 10 volts (to refresh my memory) from 12 volts.
Regards,
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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OK, let's do some math--and remember, the voltage is 12V NOMINAL--it could be as high as 14V and as low as 10-11V (at idle with lots of electrical devices on). But I'll just use the numbers you gave as an example.
So first we need to figure out the current that the 12V fan motor draws so we can determine what size resistor we need for a 2V drop across the resistor.
Power (W) = Voltage x I (current) or P = VI, or I = P/V
I = 250/12 = 20.8 rounded off to 21A. OK, so this is the current that will be flowing through the motor. Since we're going to place a resistor in series with the motor, we're going to ASSUME for these purposes that this will be the full 21A. In reality, when you reduce the voltage to a motor, it often will result in a net INCREASE in current (see ** below if you want to know why). So just to be safe I'm going to use 25A as my current value (this is me being conservative--I don't like flaming objects underneath my hood) for the purposes of resistor calculations.
OK, so now, using Ohm's law of V=IR, we know the desired voltage drop of 2V and we know the current of 25A, so we can calculate the resistor value: R = V/I = 2/25 = 0.08 ohms, or 80 milliohms. Now that's a pretty small resistor and you're going to have a hard time finding one with that value.
Let's pick a larger voltage drop of, say, 5 volts and redo the numbers to see what the resistor value would be: R = 5/25 = 0.2 ohms. Hmmm, still really low but we're getting into the 'actually available' range. Let's drop the current to 20A and recalculate: 5/20 = 0.25 ohms (this current reduction is just an arbitrary guess on my part that the motor current will be less at some level of reduced voltage, and remember that we originally started at 21A).
OK, so we're talking about a pretty low-ohm resistor here, and you could make a resistor in this range quite easily with just a piece of wire. BUT then you have to worry about the waste heat, as a piece of wire may be red hot (depending upon what size of wire you were to pick).
So now that we know the approximate value range of a resistor that we're looking for, we need to calculate the POWER dissipated in the resistor to figure out what wattage of resistor is needed. Using P = VI again, let's use 5V and 20A to get 100W--wow! That's a lot of heat!! In actuality, at this voltage drop across the resistor, we're talking about 7-9 volts across the motor, and the current at that voltage may be less than 20A. Want to check for yourself? Then find a 6V battery that's capable of running a motor this big and hook up the motor directly and monitor the current into the motor. Once you know the current draw at 6V, you will know two points on the curve and can roughly extrapolate the current draw up to full voltage (it probably is not linear, but close enough for your purposes).
And you have to mount your power resistors in such a way as they can dissipate the heat, so you DON'T wrap them with electrical tape or put wiring loom over them (it will all melt). On lots of cars I have seen in the junkyards, they put the power resistor on one of the fan motor supports such that it gets a lot of cooling air blown over it.
So hopefully you're learning how to approach these calculations. So let's say that you figure out you need a 0.25 ohm, 100W power resistor, but you can't find one anywhere. Well, you can take four 1 ohm, 25W resistors and place them in parallel and 'POOF'--you have made your very own 0.25 ohm, 100W resistor! When you parallel resistors, you add the power ratings but add the inverse of the resistances (google 'parallel resistor formula').
Now using a resistor to lower the motor's speed is the simplest way to do it, but it certainly is not the most efficient way to do it! On most GM cars since the late 1980s (my 1988 Buick has it), a PWM fan motor control module has been used in place of the series power resistors for the HVAC blower motor--this chops the DC into pulses of which the time duration or width is varied (called the duty cycle) in order to vary the power supplied to the motor. This is much more expensive than the resistors, but much more efficient.
If I were you, I'd simply go out to the auto boneyard and scrounge around (look at late 1980s-mid 1990s GMs as a start as I am pretty sure I have seen radiator fan motor resistors on this vintage) for a fan speed resistor which will most likely be in the ballpark as far as resistance and power handling goes (mix-n-match! Buy a handful and try in series and in parallel). You could also scrounge a few HVAC blower motor resistors (typically these are open-air resistors which are in the airflow path of the blower and are bare metal so you wouldn't want to short them) and adapt something with these (series/parallel combinations until you find the speed that you want). Why reinvent the wheel? And most junkyards almost give away that kind of stuff.
** DC Motors 101, reverse EMF discussion: Any time you take a loop of wire and move it through a magnetic field, it induces a voltage on that loop. This is true in a generator, but ALSO happens in a motor (I'm thinking of the simplest DC motor example here). In order to make an electrical machine a motor, you apply an external voltage or ElectroMotive Force (EMF) to the terminals. Once the rotor in the motor starts turning, guess what? That loop of wire that you are applying the forward or applied EMF to is now rotating in the magnetic field (which is either created by an electromagnet aka the field windings, or by permanent magnets, as is probably the case for this fan motor), and this generates an EMF which is the OPPOSITE POLARITY of the applied or forward EMF, hence the term reverse EMF or 'back EMF.' So the faster that the rotor in the motor turns, the higher this level of reverse EMF is.
At a standstill, the motor will take a very large current (called the inrush current, starting current, or locked-rotor current) because the reverse EMF is zero and the only thing limiting the current within the motor is the resistance within the circuit through the motor (windings, brush-commutator connection, terminals, etc). As the motor starts up and gains speed, the reverse EMF increases, opposing the applied EMF which is usually fixed, and this voltage difference between the two determines the current that will flow through the motor.
So if you apply less than the rated voltage to a motor, it won't be turning as fast, resulting in a lower EMF and thus a higher current. Similarly, when you apply a higher load to the motor, it causes its speed to decrease, which decreases the back EMF, so the difference between forward EMF and the reverse EMF becomes greater, and this higher voltage difference then causes more current to flow into the motor which increases the torque and then the speed of the motor will reach a new equilibrium point (assuming that the torque demanded of the motor is within its limits).
Feel smarter now? I used to work for a company which made aerial lift equipment and I was the engineer for the DC motor drive systems. I found a 1940s book on DC motors in a used bookstore and read it over and over again until the light bulb finally came on. Let me tell you, sometimes those early textbooks are WAY better than any current book you can find--they did a much better job of explaining things, as that was in a time when the goal of writing books was to effectively communicate information as opposed to stoking the ego of college professors and enriching textbook publishing companies. I think the book that I have was originally written in the early 1920s and the revised version I had was from the late 1940s.
So first we need to figure out the current that the 12V fan motor draws so we can determine what size resistor we need for a 2V drop across the resistor.
Power (W) = Voltage x I (current) or P = VI, or I = P/V
I = 250/12 = 20.8 rounded off to 21A. OK, so this is the current that will be flowing through the motor. Since we're going to place a resistor in series with the motor, we're going to ASSUME for these purposes that this will be the full 21A. In reality, when you reduce the voltage to a motor, it often will result in a net INCREASE in current (see ** below if you want to know why). So just to be safe I'm going to use 25A as my current value (this is me being conservative--I don't like flaming objects underneath my hood) for the purposes of resistor calculations.
OK, so now, using Ohm's law of V=IR, we know the desired voltage drop of 2V and we know the current of 25A, so we can calculate the resistor value: R = V/I = 2/25 = 0.08 ohms, or 80 milliohms. Now that's a pretty small resistor and you're going to have a hard time finding one with that value.
Let's pick a larger voltage drop of, say, 5 volts and redo the numbers to see what the resistor value would be: R = 5/25 = 0.2 ohms. Hmmm, still really low but we're getting into the 'actually available' range. Let's drop the current to 20A and recalculate: 5/20 = 0.25 ohms (this current reduction is just an arbitrary guess on my part that the motor current will be less at some level of reduced voltage, and remember that we originally started at 21A).
OK, so we're talking about a pretty low-ohm resistor here, and you could make a resistor in this range quite easily with just a piece of wire. BUT then you have to worry about the waste heat, as a piece of wire may be red hot (depending upon what size of wire you were to pick).
So now that we know the approximate value range of a resistor that we're looking for, we need to calculate the POWER dissipated in the resistor to figure out what wattage of resistor is needed. Using P = VI again, let's use 5V and 20A to get 100W--wow! That's a lot of heat!! In actuality, at this voltage drop across the resistor, we're talking about 7-9 volts across the motor, and the current at that voltage may be less than 20A. Want to check for yourself? Then find a 6V battery that's capable of running a motor this big and hook up the motor directly and monitor the current into the motor. Once you know the current draw at 6V, you will know two points on the curve and can roughly extrapolate the current draw up to full voltage (it probably is not linear, but close enough for your purposes).
And you have to mount your power resistors in such a way as they can dissipate the heat, so you DON'T wrap them with electrical tape or put wiring loom over them (it will all melt). On lots of cars I have seen in the junkyards, they put the power resistor on one of the fan motor supports such that it gets a lot of cooling air blown over it.
So hopefully you're learning how to approach these calculations. So let's say that you figure out you need a 0.25 ohm, 100W power resistor, but you can't find one anywhere. Well, you can take four 1 ohm, 25W resistors and place them in parallel and 'POOF'--you have made your very own 0.25 ohm, 100W resistor! When you parallel resistors, you add the power ratings but add the inverse of the resistances (google 'parallel resistor formula').
Now using a resistor to lower the motor's speed is the simplest way to do it, but it certainly is not the most efficient way to do it! On most GM cars since the late 1980s (my 1988 Buick has it), a PWM fan motor control module has been used in place of the series power resistors for the HVAC blower motor--this chops the DC into pulses of which the time duration or width is varied (called the duty cycle) in order to vary the power supplied to the motor. This is much more expensive than the resistors, but much more efficient.
If I were you, I'd simply go out to the auto boneyard and scrounge around (look at late 1980s-mid 1990s GMs as a start as I am pretty sure I have seen radiator fan motor resistors on this vintage) for a fan speed resistor which will most likely be in the ballpark as far as resistance and power handling goes (mix-n-match! Buy a handful and try in series and in parallel). You could also scrounge a few HVAC blower motor resistors (typically these are open-air resistors which are in the airflow path of the blower and are bare metal so you wouldn't want to short them) and adapt something with these (series/parallel combinations until you find the speed that you want). Why reinvent the wheel? And most junkyards almost give away that kind of stuff.
** DC Motors 101, reverse EMF discussion: Any time you take a loop of wire and move it through a magnetic field, it induces a voltage on that loop. This is true in a generator, but ALSO happens in a motor (I'm thinking of the simplest DC motor example here). In order to make an electrical machine a motor, you apply an external voltage or ElectroMotive Force (EMF) to the terminals. Once the rotor in the motor starts turning, guess what? That loop of wire that you are applying the forward or applied EMF to is now rotating in the magnetic field (which is either created by an electromagnet aka the field windings, or by permanent magnets, as is probably the case for this fan motor), and this generates an EMF which is the OPPOSITE POLARITY of the applied or forward EMF, hence the term reverse EMF or 'back EMF.' So the faster that the rotor in the motor turns, the higher this level of reverse EMF is.
At a standstill, the motor will take a very large current (called the inrush current, starting current, or locked-rotor current) because the reverse EMF is zero and the only thing limiting the current within the motor is the resistance within the circuit through the motor (windings, brush-commutator connection, terminals, etc). As the motor starts up and gains speed, the reverse EMF increases, opposing the applied EMF which is usually fixed, and this voltage difference between the two determines the current that will flow through the motor.
So if you apply less than the rated voltage to a motor, it won't be turning as fast, resulting in a lower EMF and thus a higher current. Similarly, when you apply a higher load to the motor, it causes its speed to decrease, which decreases the back EMF, so the difference between forward EMF and the reverse EMF becomes greater, and this higher voltage difference then causes more current to flow into the motor which increases the torque and then the speed of the motor will reach a new equilibrium point (assuming that the torque demanded of the motor is within its limits).
Feel smarter now? I used to work for a company which made aerial lift equipment and I was the engineer for the DC motor drive systems. I found a 1940s book on DC motors in a used bookstore and read it over and over again until the light bulb finally came on. Let me tell you, sometimes those early textbooks are WAY better than any current book you can find--they did a much better job of explaining things, as that was in a time when the goal of writing books was to effectively communicate information as opposed to stoking the ego of college professors and enriching textbook publishing companies. I think the book that I have was originally written in the early 1920s and the revised version I had was from the late 1940s.
1982 Datsun 720 King Cab, SD22, 86K miles (sold)
1981 Rabbit LS 4-door, 1.6D, 130K miles (sold)
1996 Passat TDI 4-door sedan, 197K miles
1981 Rabbit LS 4-door, 1.6D, 130K miles (sold)
1996 Passat TDI 4-door sedan, 197K miles
- asavage
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redmondjp wrote:On lots of cars I have seen in the junkyards, they put the power resistor on one of the fan motor supports such that it gets a lot of cooling air blown over it . . . .
If I were you, I'd simply go out to the auto boneyard and scrounge around (look at late 1980s-mid 1990s GMs as a start as I am pretty sure I have seen radiator fan motor resistors on this vintage) for a fan speed resistor which will most likely be in the ballpark as far as resistance and power handling goes . . .
asavage wrote:Save yourself some grief: get a big dropping resistor from any 80's Taurus at a JY, wire it in series with your fan(s), mount a switch near your dash, and wire the switch to bypass (short out) the big resistor. Efficient? No, you'll have heat dissipation to deal with, the resistor will be dropping 2-4 volts but a lot of current. But simple and reliable. Two fan speeds is enough.
I don't think the current-handling of the HVAC resistors is high enough for a pair of radiator fans.redmondjp wrote:You could also scrounge a few HVAC blower motor resistors . . .
Wow! I haven't heard anybody except myself say "back EMF" since 1981 when I took my automotive tech training.redmondjp wrote:** DC Motors 101, reverse EMF discussion. . . .
Thanks for taking the time to post all this.
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
- ecomike
- Posts: 242
- Joined: 18 years ago
- Location: Houston Tx
I checked out the stud and nut the other day looking for larger nuts (which I did not find), I am pretty sure it is 5 mm, just checked it with a ruler.
My Alternator shop expert said the resistor should be no larger than 1/2, 0.5 ohms in the switched L wire. I don't think the current flow there is significant.
Personally I am not impressed with a 5 mm stud and mini nuts for carrying 50 amps!
My Alternator shop expert said the resistor should be no larger than 1/2, 0.5 ohms in the switched L wire. I don't think the current flow there is significant.
Personally I am not impressed with a 5 mm stud and mini nuts for carrying 50 amps!
![Shocked :shock:](./images/smilies/icon_eek.gif)
asavage wrote: Output: no plug, but a 5mm stud I think.
Regards,
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
- asavage
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My guess is that it's quite a bit higher resistance than 0.5 ohms (OEM).ecomike wrote:My Alternator shop expert said the resistor should be no larger than 1/2, 0.5 ohms in the switched L wire.
Of course not, not through the idiot lamp. However, what if yours is not wired though the lamp? Turn the key ON, current flows from some 12v+ source through some resistor and to the field, which does NOT need much to kick-start it. I can see field overheating if you left it not running very long, if the resistor isn't large enough.I don't think the current flow there is significant.
I'd guess that you could see 4-10 amps there, which the wiring could probably handle but the non-rotating (non-fan-cooled) rotor might not, due to lack of heat dissipation.
Another scenario: no serious resistor on that line, and you fry a fusible line or some other main feed failure. That wire is suddenly going to go near ground potential, a lot of amps are going to try to flow from the diode trio (designed for maybe 10a on a good day) through the L terminal to your 12v+ source -- probably a switched hot leading to the Ign. switch. In that case, you'd definitely see smoking wire, until the diode trio expired.
Leaving a resistor out (and without an idiot lamp in the circuit) will work. It just won't be safe (if I've made correct assumptions).
Nissan added an extra part for a reason. Are we "good" enough to second guess their engineers? Maybe. Maybe not.
It's lasted 25 years, hasn't it? You can't put much torque on it, but then again, the diodes are not all that robust so why bother? I'd like a 5/16" (8mm) stud, but you generally don't get that large a mount until commercial equipment.Personally I am not impressed with a 5 mm stud and mini nuts for carrying 50 amps!
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
- ecomike
- Posts: 242
- Joined: 18 years ago
- Location: Houston Tx
Just ran some ohm meter tests.
And with the battery disconnected, alternator disconnected, and ignition switch off, or ignition switch on, I get 1.2 ohms of resistance from the L (or WL, what ever you wish to call it, FSM uses both, one for wire color WL, the other for wire designation L) pin on the female connector that attaches to the alternator, to the battery ground clamp (disconnected from battery but still wired to the body & frame ground).
In other words my L line is grounded.
I thought it was suppose to be getting a 12 volt switched signal through the ignition switch? Which is it, or which should it be????
I will check the wiring again in the morning, but from what I found, it is not shorted to ground, it has been wired to ground for 5 years!
redmondjp,
I just found your last post. Some how I missed it earlier. Very NICE post. Thanks. I agree with you about very old text books, and some EGO massaging professors. So if I understand you correctly, using a voltage dropping resistor on a DC fan motor is not going to reduce the current, it will only reduce the voltage across the motor? Some how I was thinking the slow fan speed would reduce the fan motor power load. Oh, never mind, now I see it, the resistor uses the rest of power and waists it as heat. But why would a DC motor pull more power at a slower speed?
For some reason it never dawned on me that the current might be higher when the fan speed was lower due to the speed control resistors. But if that is true, then why does my volt meter (dash gauge) voltage drop, and my head lights dim when I have the AC blower on max speed (and that is the only time it ever blew the original 25 amp resistors, was at max speed)?
For what it is worth the speed control resistors on the Jeeps (mine are jeeps) are in the AC vent, duct work, and they are wire resistors but they are also wound into coils, not straight wires!!! Doesn't that change the calculation on the heat loss, or something? It affects the back EMF as I recall. Perhaps it reduces the net power when the coil resistor is used?
Anyway, the only reason I wanted to slow the fans down was to reduce the load on the battery and alternator system, which is why I was planning to use a 600 watt, 120 volt dimmer switch, and not a resistor. Do you see any reason the dimmer switch would not work to reduce the power used and fan speeds at the same time?
![Shocked :shock:](./images/smilies/icon_eek.gif)
In other words my L line is grounded.
![Shocked :shock:](./images/smilies/icon_eek.gif)
I thought it was suppose to be getting a 12 volt switched signal through the ignition switch? Which is it, or which should it be????
I will check the wiring again in the morning, but from what I found, it is not shorted to ground, it has been wired to ground for 5 years!
![Shocked :shock:](./images/smilies/icon_eek.gif)
redmondjp,
I just found your last post. Some how I missed it earlier. Very NICE post. Thanks. I agree with you about very old text books, and some EGO massaging professors. So if I understand you correctly, using a voltage dropping resistor on a DC fan motor is not going to reduce the current, it will only reduce the voltage across the motor? Some how I was thinking the slow fan speed would reduce the fan motor power load. Oh, never mind, now I see it, the resistor uses the rest of power and waists it as heat. But why would a DC motor pull more power at a slower speed?
For some reason it never dawned on me that the current might be higher when the fan speed was lower due to the speed control resistors. But if that is true, then why does my volt meter (dash gauge) voltage drop, and my head lights dim when I have the AC blower on max speed (and that is the only time it ever blew the original 25 amp resistors, was at max speed)?
For what it is worth the speed control resistors on the Jeeps (mine are jeeps) are in the AC vent, duct work, and they are wire resistors but they are also wound into coils, not straight wires!!! Doesn't that change the calculation on the heat loss, or something? It affects the back EMF as I recall. Perhaps it reduces the net power when the coil resistor is used?
Anyway, the only reason I wanted to slow the fans down was to reduce the load on the battery and alternator system, which is why I was planning to use a 600 watt, 120 volt dimmer switch, and not a resistor. Do you see any reason the dimmer switch would not work to reduce the power used and fan speeds at the same time?
Regards,
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
- asavage
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Oh, Mike, you make the most amusing assumptions ![Smile :)](./images/smilies/icon_smile.gif)
No, the wire isn't grounded.
Imagine that the wire connected to the L terminal is connected to, say, the back of your Ign. switch. Imagine that there are other things also connected to the back of the switch, so that when you turn ON the switch (presumably, using your key), those other things get 12v+ too, just like the wire leading to the L terminal.
Imagine one of those things is, say, a lamp. Let's say it's an idiot lamp for something, doesn't matter what. That lamp has a ground.
Now turn OFF the Ign. switch (as in your test). Your ohmmeter is connected to the wire for the L terminal, and to the harness ground -- the same ground used by that idiot lamp. Ohmmeter measures the path: "from" meter lead No. 1 at the L terminal, up to the Ign. switch, from the switch to the idiot lamp, through the lamp and "to" ground: ohmmeter lead No. 2.
You've measured the reductive resistance of all parallel grounded loads that are switched by the Ign. switch and that are active with Key ON Engine OFF.
IOW, you will not be able to determine the resistance of the wire to the L terminal using that method. You have to figure out the point closest to the switch (presumably the Ign. switch, but possibly a downstream relay) that that wire connects, and place lead No. 2 there -- not ground.
I'd like you to consider continuing this in a different thread, as it really has little to do with my original topic of Hitachi alternators.
EMF is (AFAICR) related only to inductive fields (loads), not resistive loads.
![Smile :)](./images/smilies/icon_smile.gif)
The terminal is Terminal L; the wire color is WL, as you stated. I refer to the terminal designation most of the time, when talking circuit theory and operation, and sometimes switch to the wire color when describing diagnostic procedures.ecomike wrote:Just ran some ohm meter tests.And with the battery disconnected, alternator disconnected, and ignition switch off, or ignition switch on, I get 1.2 ohms of resistance from the L (or WL, what ever you wish to call it, FSM uses both, one for wire color WL, the other for wire designation L) pin on the female connector that attaches to the alternator, to the battery ground clamp (disconnected from battery but still wired to the body & frame ground).
In other words my L line is grounded.
No, the wire isn't grounded.
Imagine that the wire connected to the L terminal is connected to, say, the back of your Ign. switch. Imagine that there are other things also connected to the back of the switch, so that when you turn ON the switch (presumably, using your key), those other things get 12v+ too, just like the wire leading to the L terminal.
Imagine one of those things is, say, a lamp. Let's say it's an idiot lamp for something, doesn't matter what. That lamp has a ground.
Now turn OFF the Ign. switch (as in your test). Your ohmmeter is connected to the wire for the L terminal, and to the harness ground -- the same ground used by that idiot lamp. Ohmmeter measures the path: "from" meter lead No. 1 at the L terminal, up to the Ign. switch, from the switch to the idiot lamp, through the lamp and "to" ground: ohmmeter lead No. 2.
You've measured the reductive resistance of all parallel grounded loads that are switched by the Ign. switch and that are active with Key ON Engine OFF.
IOW, you will not be able to determine the resistance of the wire to the L terminal using that method. You have to figure out the point closest to the switch (presumably the Ign. switch, but possibly a downstream relay) that that wire connects, and place lead No. 2 there -- not ground.
The resistor will cause the voltage will drop, and the lower voltage will not be able to push as many coulombs: the amperage (current) will drop. Some heat will be generated by the resistor whilst it reduces the voltage/current (both).. . . using a voltage dropping resistor on a DC fan motor is not going to reduce the current, it will only reduce the voltage across the motor?
Can we just take it as given that it does? Google on the topic for more info.But why would a DC motor pull more power at a slower speed?
I'd like you to consider continuing this in a different thread, as it really has little to do with my original topic of Hitachi alternators.
EMF is (AFAICR) related only to inductive fields (loads), not resistive loads.
A dimmer switch is a phase chopper, and you have no phase to chop. Use a Taurus dropping resistor for low fan speed and a bypass switch to short across the resistor for high speed. Cheap. Easy. Easy to diagnose, hard to break. Two wires to cockpit.Anyway, the only reason I wanted to slow the fans down was to reduce the load on the battery and alternator system, which is why I was planning to use a 600 watt, 120 volt dimmer switch, and not a resistor. Do you see any reason the dimmer switch would not work to reduce the power used and fan speeds at the same time?
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
- ecomike
- Posts: 242
- Joined: 18 years ago
- Location: Houston Tx
Well I dug into my wiring further and it turns out the prior owner connected (spliced) the ignition switch +12 volt signal wire that feeds the starter solenoid, to the L connection on the alternator, spliced about 18" back into the wiring harness from the alternator and starter solenoid.
So "L" sees a momentary low battery cranking voltage (about 11 volts in my case) only when the starter is switched on and when the starter is cranking the engine. After that the L wire sees the ground through an un-powered starter solenoid that reads about 0.2 ohms to ground. I did not find a resistor in the circuit, just the starter solenoid coil, between L and ground.
So now I know how this beast is, was wired by the PO, compared to the OEM Nissan setup.
So "L" sees a momentary low battery cranking voltage (about 11 volts in my case) only when the starter is switched on and when the starter is cranking the engine. After that the L wire sees the ground through an un-powered starter solenoid that reads about 0.2 ohms to ground. I did not find a resistor in the circuit, just the starter solenoid coil, between L and ground.
So now I know how this beast is, was wired by the PO, compared to the OEM Nissan setup.
Regards,
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
- asavage
- Site Admin
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- Joined: 18 years ago
- Location: Oak Harbor, Wash.
- Contact:
Re: Hitachi LR150 50A alternator
One of our members, Corky Peterson, had a recurring oil leak in his alternator. He had the usual groove in the rotor's shaft, but -- unusually -- the usual fix of installing the double-lip seal did not cure his problem.
He was contemplating attempting to have the shaft flame-sprayed and turned (though I have my doubts about that working on a rotor), but decided to go with a Speedi-Sleeve instead.
The one he's using is an
SKF 99059, about $30 (May2014)
Here's a link to a YouTube promo. Be sure & dig the disco soundtrack. The link is to the section where they show the product, 1:22 in.
![Image](http://asavage.dyndns.org/Nissan/SKF-99059.jpg)
In the generic Speedi-Sleeve pic above, the sleeve is on the right, and the included install tool is the closed-end piece on the left, which I don't think could be used on a long shaft like the rotor on the LR-series alternators, but I'm sure that could be worked around. The promo vid shows a much longer install tool. The promo vid doesn't mention it, but I think I've used LocTite green when mounting these sleeves in the past.
Here's a PDF from SKF on these. They're type 304 stainless steel. and the wall thickness is 0.010" (0.254mm) -- a different SKF source quotes this as 0.28mm (0.011"). Reading in the PDF, the sleeves are an interference fit, so they don't just slide on with light force. "No adhesive is required," so maybe I'm remembering wrong when I mentioned LocTite green.
"If the tool is not long enough a length of pipe of tubing with square, deburred ends can be used instead."
![Image](http://asavage.dyndns.org/Nissan/Speedi-sleeve_04b.png)
![Image](http://asavage.dyndns.org/Nissan/Speedi-sleeve_02b.png)
![Image](http://asavage.dyndns.org/Nissan/720/Alternator/Rotor_02b.jpg)
![Image](http://asavage.dyndns.org/Nissan/720/Alternator/Alt-LR150-133E_02b.jpg)
SKF has this nifty chart, which implies that the T304SS is not as robust to further seal wear as, perhaps, the original shaft -- but better than a flame spray build-up, I'd think.
![Image](http://asavage.dyndns.org/Nissan/Speedi-sleeve_03b.png)
The "Gold" version isn't available for 15mm shaft size, unfortunately.
He was contemplating attempting to have the shaft flame-sprayed and turned (though I have my doubts about that working on a rotor), but decided to go with a Speedi-Sleeve instead.
The one he's using is an
SKF 99059, about $30 (May2014)
Here's a link to a YouTube promo. Be sure & dig the disco soundtrack. The link is to the section where they show the product, 1:22 in.
![Image](http://asavage.dyndns.org/Nissan/SKF-99059.jpg)
In the generic Speedi-Sleeve pic above, the sleeve is on the right, and the included install tool is the closed-end piece on the left, which I don't think could be used on a long shaft like the rotor on the LR-series alternators, but I'm sure that could be worked around. The promo vid shows a much longer install tool. The promo vid doesn't mention it, but I think I've used LocTite green when mounting these sleeves in the past.
Here's a PDF from SKF on these. They're type 304 stainless steel. and the wall thickness is 0.010" (0.254mm) -- a different SKF source quotes this as 0.28mm (0.011"). Reading in the PDF, the sleeves are an interference fit, so they don't just slide on with light force. "No adhesive is required," so maybe I'm remembering wrong when I mentioned LocTite green.
"If the tool is not long enough a length of pipe of tubing with square, deburred ends can be used instead."
![Image](http://asavage.dyndns.org/Nissan/Speedi-sleeve_01b.png)
![Image](http://asavage.dyndns.org/Nissan/Speedi-sleeve_04b.png)
SKF wrote:Remove the flange if necessary. It is important that this is only done after the sleeve has reached its final position. The flange should be cut through to the tear groove after which it can be peeled off along the groove using a pair of tongs. If the flange is not in the way when other parts are being assembled and if it will not foul another component in operation, it is recommended that it be left in position.
![Image](http://asavage.dyndns.org/Nissan/Speedi-sleeve_02b.png)
The chart shows the install tool for the 15mm dia. 99059 to be 47mm long, which is about 1-7/8" long. I'm not certain if that is long enough to install the sleeve on an LR1x0 rotor fully. Maybe yes, maybe no. Somebody will have to measure a rotor at the splines end.SKF wrote:Removal: A Speedi-Sleeve can be dismounted in one of the following ways: by applying heat to the sleeve; by using a pair of wire cutters starting at or near the flange and applying a twisting action; by “peening” with a small hammer across the full width of the sleeve to expand it or, if accessible, by using a drift on the flange. A Speedi-Sleeve cannot be re-used.
If the flange is to be removed, it should be cut from the outside diameter into the radius in one location prior to installation. The flange can then be rotated and raised up after installation and grasped with a pliers and twisted into a coil.
It should be noted that heat may never be used to install an SKF SPEEDI-SLEEVE.
![Image](http://asavage.dyndns.org/Nissan/720/Alternator/Rotor_02b.jpg)
![Image](http://asavage.dyndns.org/Nissan/720/Alternator/Alt-LR150-133E_02b.jpg)
SKF has this nifty chart, which implies that the T304SS is not as robust to further seal wear as, perhaps, the original shaft -- but better than a flame spray build-up, I'd think.
![Image](http://asavage.dyndns.org/Nissan/Speedi-sleeve_03b.png)
The "Gold" version isn't available for 15mm shaft size, unfortunately.
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
-
- Posts: 891
- Joined: 16 years ago
- Location: Cochrane Alberta Canada
Re: Hitachi LR150 50A alternator
Used these for years back in the day. The piece of pipe you mention is the method we used to install as well. We also found that the flange piece ( that is meant to come off in some applications ) that went up to the bearing acted like a slinger which helped keep the oil away. It can be a bit of a PITA to remove if you have to and pounding it too hard putting it on will break it off during install and then you are pooched and have to buy another one. I did not however realize they were this expensive now.
IIRC back then they were only a few dollars.
Driving them on perfectly straight is the biggest challenge. If they are tilted too much they will tear, and at this price that would annoy me. ( I have not used one this small however as 7/8" was the smallest diameter shaft we used them on)
Getting them started on a tapered shaft was pretty easy but there was one shaft that we used them on that was straight cut at the end and I remember tearing a couple of them putting them on.
That being said I may have been in a hurry and not paying attention too. ( which is the most likely scenario)
We always used the standard speedy sleeve back then and some of the units we used them on had 400+ hours on them when they came in for rebuild and were not leaking. I guess it depends on how hard the seal becomes over time.
IIRC back then they were only a few dollars.
Driving them on perfectly straight is the biggest challenge. If they are tilted too much they will tear, and at this price that would annoy me. ( I have not used one this small however as 7/8" was the smallest diameter shaft we used them on)
Getting them started on a tapered shaft was pretty easy but there was one shaft that we used them on that was straight cut at the end and I remember tearing a couple of them putting them on.
That being said I may have been in a hurry and not paying attention too. ( which is the most likely scenario)
We always used the standard speedy sleeve back then and some of the units we used them on had 400+ hours on them when they came in for rebuild and were not leaking. I guess it depends on how hard the seal becomes over time.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
- asavage
- Site Admin
- Posts: 5431
- Joined: 18 years ago
- Location: Oak Harbor, Wash.
- Contact:
Re: Hitachi LR150 50A alternator
The PDF I linked to has some tips on removal that sounded reasonable, including the peening method (to stretch the material and make it larger dia.) and heat.
I can well believe that tearing during install is easy. I haven't used one in at least 30 years, and have only fuzzy memories of them.
It's too bad the Gold version isn't available in our size. The wear rating quoted for abrasive stress test was 450 hours vs 2500 hours to failure.
I can well believe that tearing during install is easy. I haven't used one in at least 30 years, and have only fuzzy memories of them.
It's too bad the Gold version isn't available in our size. The wear rating quoted for abrasive stress test was 450 hours vs 2500 hours to failure.
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
-
- Posts: 891
- Joined: 16 years ago
- Location: Cochrane Alberta Canada
Re: Hitachi LR150 50A alternator
Agreed, but if one were to just change the seal out every 2 - 3 years or so before it gets too hard I think the standard sleeve would last beyond ones love for the vehicle.,,,,,,,,,,,,,,,,,,,,,,,,,maybe.
![Smile :)](./images/smilies/icon_smile.gif)
![Smile :)](./images/smilies/icon_smile.gif)
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
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