Home Forums General Discussion Technical Questions Otis 10NOCL 2spd AC

Ok. Here's the scenario. Motor got hot and the smoke escaped. Sent motor out for repair. Get motor reinstalled and car runs in correct direction and at correct speeds (50fpm car). Motor data tag says FLA 17.6. In high speed we are getting 40A. In low speed we are getting 30A. All contactors are good, all resistors are good, all wiring is new from controller to motor and wired correctly. We bypass the controller and wire motor directly to our 240V source and high speed is 10A both directions, and low speed draws 50A! Both directions. Power source is a confirmed 240V on all three legs. Motor gets hot. We have never blown a fuse or popped an overload. (we don't run it long). Pulled motor again, and this time pulled the worm shaft (14AT machine) so the motor shop can assemble and actually run it this time. Any theories and/or ideas?

Are you pulling the the same amperage in both directions? The counterweights should be 40 to 50 percent heavier than the car. Therefore you should pull less amps empty car up, and more amps empty car down. If you are pulling the same amount in both directions the car and counterweights weigh about the same, and the car is too heavy.

Can you drift the car by picking brake to see if there are any binds?

Machine rolls smooth. Can turn sheave using hand crank even without picking the brake it rolls that good. Tiny car and it's a 14AT pinion gear drive machine. Amperages were close up/and down through the controller. Wired direct to 240V power it's way off high speed versus low speed. Personally I think it's wired wrong in the windings. Motor is on it's way back to the shop, a very reputable one at that, so they should know what they're doing.

If you can turn that easily, something is wrong with counterweighing. Balance load should be 40% of duty load for that equipment.

A quick test of thee windings would normally be a higher resistance for the slow speed compared to the fast speed. So i think that you should match your resistance measurements with disconnected winding, as you may have cross contaminated windings. Use the resistance and voltage measurements and use ohms law to see if it is what its supposed to be, and compare what you are getting.

Check rotor for cracked / broken rotor bars and get them repaired if that is the case.

You should do resistance or insulation test prior to powering up.

One faulty wiring can cause lots of issues.

Motor was wound wrong. On it's way back to us for the 2nd time.

Theres no way that could happen. Motor has to be rewired incorrectly

Oh Crap. Just saw that last response when hitting post. Lol

Thought it may be something like this. We had a genny come back to us, do all sorts of weird things including a shorted shunt field which the lift just rolled away. Found the series and shunt fields all wound wrong and the terminals all wrong too.

Oh crap. Shite happens sometimes.