Stupid question about DC motors

No. The worse than can happen is the motor(s) could be damaged. These motors are made for either about 180 to 190 volt DC and will, if using a controller, require a controller (DC motor drive) for 220 volt AC service and about 180 volt DC output. It is best you bite the bullet and aquire a DC motor drive. They can be bought from various sources but attention must be paid to current output of purchased drive. Be sure the power output of drive meets or exceeds that of the motor requirement. Normally drives for these motor voltages are rated at about 2 HP but can be more or less. It is current rating of motor and voltage rating that is needed to know before deciding on drive to use. The output current rating of drive can exceed that of motor but not less than.

RL
 
As long as you hook up the current to the right wires on the motor you are OK.You need to know the field wires and the armature wires.If it is a permag motor you can test it with 12VDC.If it requires a field voltage,you need a controller.
SA
 
I tested my motor with a car battery. Nice source of clean DC current. BTW if there's only two leads on the motor you can't do it wrong. All the DC motors I know of spin either direction. Reverse the leads - reverse the direction.

BTW I use a 180 vdc 2 hp treadmill motor on my KMG. And the controller only goes to 90 volts! No big deal, so it only reaches half the maximum RPMs. You don't HAVE to run a DC motor at full voltage. I use pulleys so that get the speed I want from 20 to 90 volts.

Steve
 
spin the motors by hand first and make sure they turn freely etc. If they are rusty inside or the motor has taken a set because of the magnets you might have a problem.
 
Any motor operated with marginal current source can load due to possible loading placed upon motor, even if motor is unloaded. It is most important to provide optimal or greater source current.

RL
 
Good point Roger. While less than max voltage is a so what, a controller with less than max current (HP) is a real problem, for the controller.

Steve
 
Motors are really quite simple beasts. Either they are bad mechanically and/or electrically.

Check for smooth rotation as Tom suggested. If it will not turn, put it in the trash.

The current drawn by a DC motor should decrease with the applied voltage, with a constant (or zero) load. The motor should draw relatively little current at 12V (a few amps for an unloaded motor of this size) so the capacity of the source/charger that you use for this test is not really critical. A DC motor controller simulates various DC levels to control the speed of the motor. It will put out something like 12V to give you a low motor speed.

Using a 12V battery or charger should be OK as Sando has discovered. The charger is probably the best option since it would be plugged into a house circuit with a breaker. There is very little to limit the current drawn from a car battery and you can/will melt things if the motor is shorted internally.

It might be best if you connect one wire from the charger then just brush the other on the motor wire and see if the motor shaft tries to move. If it does then hold it on longer. If the motor is shorted internally, you might not see any shaft movement. Your charger should be OK with the momentary high current drawn by a shorted motor but it probably won't like being connected for longer periods. If you use a proper DC motor controller as Roger has suggested, it should be able to protect itself against a shorted motor.

I hope that this makes sense. Good luck.

Phil
 
Hello Mark

I just checked and the inventory system that I have access to show some in stock. I sent an e-mail to Shane who is in charge over there since they have all gone home now. I will post the reply tomorrow. The part mumber is VFS7S-2015UP.

Phil
 
Hello Mark

I was able to confirm with Shane that the quantity in stock that I saw was correct. There are 37 of the the VFS7S-2015UP 2HP, single phase, 240V input drives in stock at this time. They are listed on the "fire sale list" since they are an obsolete type and are no longer in production. Just call 713 466 0277 or 800 231 1412 and ask for the Drives Marketing Department.

Let us know how it goes.

Phil
 
Thanks Phil,

I guess it is wise to deal with Shane directly. The lady I spoke with said I would have to get special approval from Shane. i'll try again when he's around. I appreciate it.
 
Just a note, some 12v battery chargers won't put out any current until they sense a voltage from the battery. That means that in open circut or pure load (no counter current being generated) they wouln't put out any power at all.
 
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