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Discussion Starter · #1 ·
Wondering about the terminals on this...and if anyone knows the brand...

I'm pretty sure it came out of a Caterpiller lift truck. Looks in very good shape on inside.... bit dirty on outside....

As for the terminals.... my first thought was connection to field windings for series/parallel switching??....but.... I thought 4 terminals were required for this?? One is labelled BWI, another F1 - E1 (the"F1" has box around it), the other is F2 - E2 (F2 has a box around it).

The pigtail is likely thermal switch connection.... yes?

Does the symbol on the tag look familiar to anyone?

This thing will likely handle gobs of current with the big bars... 37 segment comm... but maybe not so high voltage? No interpoles.. would love to fit some though.

I'm thinking to put this in my truck, direct drive.
 

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Discussion Starter · #2 ·
Here's a few more shots...

Double brushes, hardly worn. Double pig tails/brush. Nice film on the com and no visible wear. Pretty clean on inside. Has kevlar banding. 10 tooth spline.
 

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Looks like you may have a compound wound motor. Like me:D. BWI is "brush wear indicator". F1 and F2 are the shunt field terminals. Put a multimeter on there and measure the dc resistance. Mine is 18 ohms.
 

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Discussion Starter · #5 ·
Looks like you may have a compound wound motor. Like me:D. BWI is "brush wear indicator". F1 and F2 are the shunt field terminals. Put a multimeter on there and measure the dc resistance. Mine is 18 ohms.
Thank you Jack. It never even occurred to me that it was a compound wound motor...lol. I did remember what the BWI represented...after I asked...:rolleyes:

Now what? I have to learn about these motors. Can it be run purely as a Series motor on a regular controller?? If so, what am I giving up? If not, do I have to control the field like a sepex?
 

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Discussion Starter · #6 ·
Great found!!!

How and where do you find all this motors?
Is it? I'm not sure yet..lol I didn't pay much for it.... but still... I thought it was a series motor....:eek:
 

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Discussion Starter · #7 · (Edited)
Objective is to run this motor on a series DC motor control. Soliton1.

OK so, I'm trying to wrap my brain around the compound wound DC motor. I don't see any reason it couldn't be just used as a series motor without exciting the shunt field. It has a series winding anyways. Should work as a series motor. Yes? In this configuration, would it have less torque than a pure series motor due to the space taken on the field coils by the shunt windings? (I have no specs to compare it to other 13 inch series motors)

Second thought... (don't laugh) ... Is there any reason that the shunt winding cannot be connected in parallel with the series field winding?
If I connected F1 to S1 and F2 to S2...linked A2 to S1/F1 and put line on A1 and F2/S2 would this give me a motor that performed most like a regular series motor... or would I burn out the shunt winding?.... No, I don't know if it is short or long shunt connected...:eek:... yet...:)

Thanks for any comments....

I could post a sketch if it would help....??
 

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OK so, I'm trying to wrap my brain around the compound wound DC motor. I don't see any reason it couldn't be just used as a series motor without exciting the shunt field. It has a series winding anyways. Should work as a series motor. Yes? In this configuration, would it have less torque than a pure series motor due to the space taken on the field coils by the shunt windings? (I have no specs to compare it to other 13 inch series motors)

Second thought... (don't laugh) ... Is there any reason that the shunt winding cannot be connected in parallel with the series field winding?
If I connected F1 to S1 and F2 to S2...linked A2 to S1/F1 and put line on A1 and F2/S2 would this give me a motor that performed most like a regular series motor... or would I burn out the shunt winding?.... No, I don't know if it is short or long shunt connected...:eek:... yet...:)
Looking at the diagram at http://www.micromotcontrols.com/htmls/Motor characteristics.html and if you have access directly to the series winding, then (I think) you could connect the two in parallel (provided they are the same resistance) or in series. You can also put a contactor on the extra winding and short it F1-F2 if it's in series (essentially bypassing it, as the power will prefer the low-resistance short to the higher-resistance field), or just open the connection from S1-F1 if wired in parallel for a form of field weakening (I believe). In fact, you could even isolate and reverse the shunt power to create an opposing force and weaken the field even further.

Of course, this is all dependent on the windings being equivalent and able to take the power, as opposed to (for example) a SepEx motor, where the winding more than likely won't take the power.
 

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First thing is to measure the resistance of the shunt. Secondly , do you know what voltage the forklift ran at?

If you run with no shunt the amps will be very high especially if your planning direct drive. Ideally , you want a high shunt current at startup and tail off as the vehicle speed increases. Unfortunatly this is exactly opposite to what a normal controller does.

I have found the best compromise to be running about 1/3rd shunt current via a resistor and solid state relay / fwd diode setup via the pack. If you need some more info no prob. I did a few videos on the subject last year.
 

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Discussion Starter · #10 ·
First thing is to measure the resistance of the shunt.
I will measure it today... likely will bring the motor home today also.
Secondly , do you know what voltage the forklift ran at?
Yes, 48 volts.
If you run with no shunt the amps will be very high especially if your planning direct drive. Ideally , you want a high shunt current at startup and tail off as the vehicle speed increases. Unfortunatly this is exactly opposite to what a normal controller does.
Would it not run as a normal series motor with shunt open? The field coils are huge with wide, flat wound conductors. I may have to pull it apart. If I can't run it with higher voltage by advancing timing... I likely wouldn't use it.

First thing is to measure the resistance of the shunt. Secondly , do you know what voltage the forklift ran at?<br /> <br /> If you run with no shunt the amps will be very high especially if your planning direct drive. Ideally , you want a high shunt current at startup and tail off as the vehicle speed increases. Unfortunatly this is exactly opposite to what a normal controller does.<br /> <br /> I have found the best compromise to be running about 1/3rd shunt current via a resistor and solid state relay / fwd diode setup via the pack. If you need some more info no prob. I did a few videos on the subject last year.
<br /> <br />
I have found the best compromise to be running about 1/3rd shunt current via a resistor and solid state relay / fwd diode setup via the pack. If you need some more info no prob. I did a few videos on the subject last year.
Thanks Jack, I did look at one of your videos last night...but it was too late to continue. So, how do u control this shunt field current then?
 

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Is there any reason that the shunt winding cannot be connected in parallel with the series field winding?
If I connected F1 to S1 and F2 to S2...linked A2 to S1/F1 and put line on A1 and F2/S2 would this give me a motor that performed most like a regular series motor... or would I burn out the shunt winding?
Hi Guy,

You won't burn out the shunt winding because there will be practically zero current in those coils. Do a simple calculation of current division of an 18Ω resistor in parallel with a 0.01Ω resistor. It is like exciting the shunt field with one volt when it is normally excited with 48 volts. You get 1/48th rated current. Pretty much useless, so why bother.



Something bothers me about this photo. Please post up a few more images of this area when you can.

major
 

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Discussion Starter · #12 ·
Hi Guy,

You won't burn out the shunt winding because there will be practically zero current in those coils. Do a simple calculation of current division of an 18Ω resistor in parallel with a 0.01Ω resistor. It is like exciting the shunt field with one volt when it is normally excited with 48 volts. You get 1/48th rated current. Pretty much useless, so why bother.



Something bothers me about this photo. Please post up a few more images of this area when you can.

major
Yes, that makes sense. OK, I'll see what I can do. I basically stuck my Blackberry inside the comm end vent hole.... and snapped that. U think the winding is overheated... on the right side there? Actually, I remembered that I took a few pics in there...lemme go see what I have...

How would this motor perform used as a normal series motor u think?
Thank you..
 

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Discussion Starter · #13 ·
Hi Major,

This is the only other pic I have right now... I'll try and get a few more today.

Thank you.
 

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Discussion Starter · #14 ·
OK, here is another pic. Turns out, it's just the insulation, potting or whatever. I scratched it with the tip of my knife blade. It's fairly soft. Looks like this is where the stuff ran when the armature was sitting after dipping or whatever they do....?

Also, I measured the shunt field. ... 8.9 ohms. My meter seems to sit at 0.2 ohms when I touch the leads together so... may be out by that much.... Series field reads 0.2 ohms, armature measures 0.4.... I guess due to brushes.

I hooked 12 volts to it, series field only. Spun up fine.... but know I know why the motor was pulled. Drive end bearing has a groan once the shaft gets going. Sounds like bearing has dried up. Spins by hand ok with no play...
I'm glad actually, because I was wondering why this motor would have been pulled with hardly any apparent wear and tear.
 

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Discussion Starter · #15 ·
So, I guess the question now is... can I run this thing with my controller as a series motor and what voltage could it handle with advanced brush timing?

Would it put out some serious torque to drive my little pick-up direct drive? ..... with some balls? :p

Oh yes... any idea who made this thing???

Thanks again for the help. :)
 

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ok we'll call it 8 ohms. so at 48v thats 6 amps. Mine is 18 ohms and ran at 72v for 4 amps max shunt. As you have a 13" and mine is an 11" i guess that sorta makes some sense.

Yes it will run as a plain series but not as well as it could. A lot depends on how the poles are wound with respect to the different fields. As an experiment connect up to run at 12v with just series field in the direction you require. Now take two wires from the shunt and touch them to the 12v battery. Note if the motor speeds up or slows down. Reverse on the shunt terminals polarity and repeat.

The best way to drive this type of motor is to have a small controller on the shunt field that supplies max or slightly more than max current at startup and low speeds and has the facility to reduce shunt when higher rpm are required. I've threatened to do this for ages but never found the time. Instead i was running at about 3.5amps shunt via a resistor and contactor from the pack. I was never really happy. Torque would fall off dramatically at about 2400rpm. One day the shunt contactor welded closed and i had to remove the fuse to get home. The car went like a rocket still pulling at 3000rpm and sounding like a gas turbine with a blown governor! Only the ammeter gave me pause for thought displaying "ovld". That only occurs over 550amps!. Eventually i played with various resistors and now run at 1 amp shunt field via a solid state relay and a free wheel diode. In this setup the shunt greatly helps the car accelerate , keeps the amps reasonable and i can still wind up to 4k rpm if i'm feeling brave. I usually change up at 3k.

This page has picks of motor teardown and brush advance:
http://www.evbmw.com/motor.html

I'm now running at 120v and am upgrading to 144v with headway cells. I'll leave the shunt setup as is as the slight increase in voltage on the series will balance out the increased shunt current. Thats the theory at least:D

Hope this helps.

My motor was made by "MCF" which is mitsubishi caterpillar forklift. I don't like direct drive. It limits options. That said i can start off in 4th in my car no problem but the amps are high. And thats with a 350kg agm pack.
 

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Discussion Starter · #17 ·
One day the shunt contactor welded closed and i had to remove the fuse to get home. The car went like a rocket still pulling at 3000rpm and sounding like a gas turbine with a blown governor! Only the ammeter gave me pause for thought displaying "ovld". That only occurs over 550amps!. Eventually i played with various resistors and now run at 1 amp shunt field via a solid state relay and a free wheel diode. In this setup the shunt greatly helps the car accelerate , keeps the amps reasonable and i can still wind up to 4k rpm if i'm feeling brave. I usually change up at 3k.
So, how are you using the contactor? Close it for low rpm/acceleration?

Also, when the contactor welded closed, how did removing the fuse help? The control circuit was no longer working... yes? Im confused....
You're saying the car pulled well at high RPM with the shunt field open then?

thanks again Jack, most helpful!
 

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Discussion Starter · #18 · (Edited)
My motor was made by "MCF" which is mitsubishi caterpillar forklift. I don't like direct drive. It limits options. That said i can start off in 4th in my car no problem but the amps are high. And thats with a 350kg agm pack.
I have a 9" series in my truck now and I run it through the stock 5 speed standard trans. It works fine. I also have AGM's but 750kg of them.. I've pulled 1000 amps for short periods.

I too am upgrading to Lithium, 65 Calb 180Ah prismatics.

When I found this motor... I got all giddy ... thinking of the reduced weight.... gobs of torque and visions of Burube's S10 running through my little brain:eek:. I know, I know ... it has lots of tricks done to it. :rolleyes::rolleyes:
 

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Its all about picking the best compromise shunt current or devising a little pwm controller. High shunt current will result in LOTS of low end torque but the high field will mean that the armature will "run out of voltage" and hence rpm very early. This is what was happening to me at 3.5amps. With no shunt you loose field strength , and hence torque. The series then has to pull lots of amps to get the vehicle moving. At 1 amp i get the best compromise between the two.

My shunt comes on at over 5% throttle and goes off at less than 10%. I had to implement this control as i was getting insane com arcing on slow down with constant shunt. I spent some time trying to find a reason for this but could not. Once i implemented the control via throttle it went away.
 

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Discussion Starter · #20 ·
Its all about picking the best compromise shunt current or devising a little pwm controller. High shunt current will result in LOTS of low end torque but the high field will mean that the armature will "run out of voltage" and hence rpm very early. This is what was happening to me at 3.5amps. With no shunt you loose field strength , and hence torque. The series then has to pull lots of amps to get the vehicle moving. At 1 amp i get the best compromise between the two.

My shunt comes on at over 5% throttle and goes off at less than 10%. I had to implement this control as i was getting insane com arcing on slow down with constant shunt. I spent some time trying to find a reason for this but could not. Once i implemented the control via throttle it went away.
hmmm very helpful Jack. Did you put any thought into how devise a parallel controller? Would PWM be overkill? Would this level of power be ok analog?

would be nice to have specs on this motor. I wonder if power could equal a pure series machine..... or better? Likely not, or racers would be using them... unless it's a controller issue??

Do you think that a proper controller scheme would have helped the arcing problem? ... and finally (ya right:rolleyes:) I wonder about how the relationship of brush timing fits into all of this...
 
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