Is it normal for Montgomery/Kone to keep field at full force with out weakining it after door's close and cars park. I have a DC analog allen bradley drives and it's a semi busy bldg. and at any given time you could fry an egg on the motors. It's a mod job motors are Westinghouse, I'm not sure if that will make a difference.

-- Clark (pdell200@comcast.net), March 05, 2004

Answers

It's quite common for all the Drive manufacturers to keep the field energized for a few minutes after the car parks. You should be able to adjust the time.

-- Bill (elevatorman_1@msn.com), March 05, 2004.

Yeah Jim I know hence the reason for the question Montgomery's A/B drive book say's WE DO NOT WEAKEN THE FIELD, I was wondering if anyone knew how to time it out or weaken it over time. Thanks for your response.

-- Clark (pdell200@comcast.net), March 05, 2004.

Field cook-off!

First of all, I'd make sure that the motor field setting matched the hoist motor. Make sure that Allen Bradley Parameters 610 (Rated motor volts),611 (rated motor arm FLA), 612 (rated motor field current),are at name plate values. If not find out why. There is a parameter in the drive adjust section that is a timer for going to the lower voltage/current state after the car stops, as well as what that voltage is going to be. It is Allen-Bradley Parameter 674 (Field Economy Ref-% of full voltage), and 675 (Field Economy Ref-time). Look at the parms. Most of the jobs I've seen throttle back the fields when it isn't running-check your settings from the factory. Check it out.

As for the literal meaning of, "We don't weaken the field", that applies when the motor is operating, not when the motor is parked, and even then, I can't speak for mod jobs that might require a field weakening. Cheers! S.

-- Steve (magnevator@verizon.net), March 08, 2004.

Analog drives use a pot on the CA board for field calibration, unlike digital drives that allow adjustment with the service tool. A field weakening parameter (bit setting) is provided for mod jobs that require it while running. Miprom 21's go to one half field about 10 seconds after stopping. Verify name plate requirement and adjust accordingly.

-- Cliff (cliff77@att.net), March 09, 2004.