Home Forums General Discussion Technical Questions Otis two speed AC motor Mod...

We are trying to bump an Otis two speed AC motor w/ a MCE 4000 controller. There are 6 motor leads, I assume for two sets of windings. Motor data tag reads speed:1800/900 rpm, 3 phase, 60Hz, 6.75Amps, and 4.25HP. This is a 2:1 geared basement traction machine. MCE set up the drive for a VVVF induction motor. Was told by more then one reputable source that the drive should push the motor. Having hooked up one set of windings I'm not getting the motor to turn in either direction. The drive output on machine room inspection is 2.9-3.5 Amps. The windings that are not hooked up to the drive have been isolated in kearny lugs. I have voltage on the motor leads connected to the drive and the motor leads that have been isolated. My questions are, can we get this motor to run with this drive (Torqmax F5)? and do we need to (or can we) jump out the other motor leads?

Oh yeah, contract speed is 50fpm.

Did you add your encoder yet? The drive needs to see feedback from the controller in order to run.

The drive will run a 2 spd motor. Isolating the 3 leads will give you high speed.

Your prints should outline all of this.

Why are you not calling MCE's tech support on a new install?

see page 6 of the electrical engineering pocket book. you can download from the internet. it shows 3 different ways to hook up the motor, constant torque, constant horsepower and variable torque. all three setups have 2 configurations, HI spd and low speed. with constant horsepower at hi speed the connections are L1-6 L2-4 L3-5 leave 1,2,3 open. this is delta configuration. for constant horsepower at low speed winding L1-1 L2-2 L3-3 join 4,5,6 this is wye connection. If the drive parameters are correct it should spin with this configuration.

Tim is right, if you told mce that you were using the existing motor, they should have given you all the info needed on the prints and the parameter settings to get the car moving. especially with the various configurations that i outlined above from the motor book.

Already called MCE. First post might not have been clear enough. The controller was ordered with the intention of installing a new VVVF AC motor. Someone decided at the last minute to retain the original motor, which is the two speed Otis AC motor (55 ES I believe, I don't have it in front of me right now). The drive parameters have been changed to run open loop. There are no job prints for the original controller (10NOCL install 1951). Was hoping someone who had experience with this motor/controller could weigh in on the subject. However, any and all advice is more than welcome.

The motor that was spec'd for the job-do the parameters for it match exactly the existing motors parameters? Most likely not. New AC induction motors are very efficient and are pretty different from older ones-it may work for you but the end result will be a much shorter life span. With the Torque Max drive you can get this puppy to run-changing para's till you get her to move but it will be a risk and MCE will not back the drive unless they approved of the install with the old motor. You can use the high speed windings as your motor leads as you would a typical motor.

Already tried both sets of windings. What I need to know is, what should I do with the other set of windings that aren't connected to the drive. Sounds like Mr. Davidson is on the right track. I will check the EE Pocket book and see if that works...

I dont think it will work. If you ever do get it running, I wonder how long the motor will last.

Spuk!

Another thing you could try if possible would be to decouple the motor from the gearbox (ie no load) and then temporarily wire it to the correct source voltage thus bypassing the drive. While you would have exercise caution and have someone standing by the mainline this would allow you to test your motor configuration. Verify your no load current matches the data tag. Once this is done and you are certain your wiring is correct then try to incorporate the drive. Presumably, if you are running open loop which on the torqmax drive you have the one encoder switching parameter set to zero I think it's like LF 27 but I am not sure right this minute, you might need to play with your slip frequency adjustments. Having a very high slip ratio will be like trying to move a standard shift car with the clutch not engaged. The torqmax has quite a few parameters that can screw you up if they are in the wrong spot.Make sure everything from about LF2 -LF30 is exactly right. Also verify your pattern scaling is set at something other than 0%. This may not apply to you but it does on some versions of MCE stuff.