How to hook up pallet jack motor???

[dmwahl]

I've had this motor in my garage for a couple of years, bought on craigslist from a guy who thought it was from an electric pallet jack. The real important question though is how to hook it up, specs, etc. I've searched the internet and can't find any hookup diagrams. Any ideas other than trial and error?

Motor has 4 terminals, labeled 3 4 5 and 6. Order can be seen in the attached photo.

Motor mfg/pn: Eaton type A4 pallet jack motor, part number 7209750-00

View attachment 1

 

[dnmun]

what would be even better is to have the reversing switch to use on this motor. 3-4 is the stator winding and 5-6 are the brushes so maybe you can google up the reversing switch for a forklift or similar DC traction motor to see how they wire up those motors.

i wonder if 6 and 3 end up being common to each other in both settings. maybe a connecting strap.

 

[major]

I've had this motor in my garage for a couple of years, bought on craigslist from a guy who thought it was from an electric pallet jack. The real important question though is how to hook it up, specs, etc. I've searched the internet and can't find any hookup diagrams. Any ideas other than trial and error?

Motor has 4 terminals, labeled 3 4 5 and 6. Order can be seen in the attached photo.

View attachment 1

Hi,

This is a series wound DC motor. The field coils (terminals 3 & 4) are wired in series with the armature (terminals 5 & 5) with an external connector. It is reversed by switching the polarity of the field with respect to the armature. Battery polarity does not matter. Connection as follows:

5 to one battery terminal, 6 to 3, and 4 to the other battery terminal.

For opposite rotation:

5 to one battery terminal, 6 to 4, and 3 to the other battery terminal.

Be careful. This is a 12 or 24 Volt motor. It will draw a lot of current; several hundred Amp spike on start up. It also has an undefined no load speed meaning a high voltage applied without a loaded shaft will cause overspeed and possible destruction. I'd suggest testing with a 6V battery or a weak 12V. It will spark and twist when juice is applied.

major

 

[dmwahl]

Thanks both for the help, I have some 50W 6 ohm resistors that I'm going to put in series with the battery to test at 12V. I'll do some searching on the reversing switch, maybe get lucky and find one cheap on ebay.

 

[dmwahl]

Forgot to mention the use... I'm planning to convert a riding mower to electric using one of these (I have 2 of them) so won't need reverse, but good to know for future use.

 

[dmwahl]

Any idea how it would work with a small hydrostatic riding mower? Major, I saw you did one over on diyelectriccar, thoughts?

 

[major]

Any idea how it would work with a small hydrostatic riding mower? Major, I saw you did one over on diyelectriccar, thoughts?

I've done yard tractors, but not hydrostatic drives. And the series wound DC motor may cause problems. The speed regulation sucks. At very light loads the motor speed goes very high and will likely cavitate the pump. So you'd need to use a speed controller, sense RPM and make a feedback to reduce voltage lowering RPM when the pump unloads the motor.

You really don't need a motor speed controller if you use a motor with good regulation. A PM or shunt wound DC motor is ripe for that application. That might require a starting resistor (and contactor) and setting the pump pressure limit to limit motor current within reason.

 

[dmwahl]

I'm sure you're right about using a PM or shunt wound motor. I'd probably spend as much on a controller as just buying a different motor, too bad though since I have a 24V 100Ah LiFePO4 pack just sitting around that I need to find a use for. Most of the PM motors I've seen seem to require 48V though. I'll keep an eye out on craigslist for a different motor.

 

[major]

I'm sure you're right about using a PM or shunt wound motor. I'd probably spend as much on a controller as just buying a different motor, too bad though since I have a 24V 100Ah LiFePO4 pack just sitting around that I need to find a use for. Most of the PM motors I've seen seem to require 48V though. I'll keep an eye out on craigslist for a different motor.

You could do something off the wall. If you're handy, remove 2 of the 4 series field coils and rewind with smaller wire more turns and change the motor into a compound motor. Or try separately exciting the series field with like a single cell so you'd have a 3 volt field and 24V armature. Even that might be too high and you'd really need like a one volt field supply. Since it won't vary with load you could use resistor to limit field current. For a separate field (with the existing series coils), you'd likely need about 100A. But with one of those cells, that would give you an hour's run time. Play with it. Maybe it only needs 70 or 80A. At 3 volts, it's not much power and pretty small sparks :wink:

 

[dmwahl]

I may try that. I have 2 of them, cost me $50 for the pair, so not a big deal to mess around with. My real shortage is time, but nobody here can help with that...

I like the idea of a separate field, maybe can run the field off one cell and the armature off the other 7. Would that require rewinding anything? I'm assuming field and armature windings are not internally connected if they require an external connection, right? I'll check with a dmm tonight to be sure.
[EDIT] Perhaps it would be easier to current limit the field and keep the cells all in a string, equally loaded, so I don't need a separate charger for the field cell and armature cells.

It's been many years since I've done anything major with DC motors, so my memory is a bit out of date on the topic, but I know enough to be cautious and have things strapped down and easy to disconnect at least.

 

[major]

I like the idea of a separate field, maybe can run the field off one cell and the armature off the other 7. Would that require rewinding anything? I'm assuming field and armature windings are not internally connected if they require an external connection, right?

No, not talking about rewind. And the fields are not connected to the armature internal in the reversible motor. That is done externally with the reversing contactors (or large switch).

[EDIT] Perhaps it would be easier to current limit the field and keep the cells all in a string, equally loaded, so I don't need a separate charger for the field cell and armature cells.

And active current limiter is a motor controller. Keeping the "field and cells in a string" is running it as a series motor with the regulation problem. So if you do that, put a speed sensor on it and feedback loop to the throttle to control the RPM. If you use a belt drive on a series motor, I recommend a speed sensor and cutoff so the motor won't explode if the belt fails. So if you run as a series motor with a controller and sensor, you might as well regulate RPM instead of the cutoff.

 

[dmwahl]

[EDIT] Perhaps it would be easier to current limit the field and keep the cells all in a string, equally loaded, so I don't need a separate charger for the field cell and armature cells.

And active current limiter is a motor controller. Keeping the "field and cells in a string" is running it as a series motor with the regulation problem. So if you do that, put a speed sensor on it and feedback loop to the throttle to control the RPM. If you use a belt drive on a series motor, I recommend a speed sensor and cutoff so the motor won't explode if the belt fails. So if you run as a series motor with a controller and sensor, you might as well regulate RPM instead of the cutoff.

I meant keep the cells all together in one 8S pack, run the field and armature in parallel with each other, and limit current to the field, but yes, you're right, that's either a big resistor and waste of power or a motor controller. At that point I might as well just buy a controller and regulate speed... And then, I might as well just buy a proper PM motor so I don't need a controller. I will likely pull apart one of the motors and try making it into a compound motor, but I'll save that for a winter project.