Created Date: March 03,2003

Created by: toml

I have a similar situation: 24,000 lb car and 10 stations. We use an encoder for positioning. The ac drive on this unit is Hitachi, but I 've used the GS2 drives on other applications. We also have brakes on the motors.

With how you 've described your current method of positioning, I think an ac drive would work well. You may want to use the coast to stop decel option (P1.00 = 01 on the GS2). This will prevent mechanical braking while there is drive output.

Created Date: March 03,2003

Created by: EricM

Thanks for the reply. If I can still use the brake motor, the motor's brake would be what I use to stop the transfer car. I only be able to stop it on a dime if it's going a lot slower before it gets to the home position. Any other way I would probably destroy the gearbox or the motor. My primary concern is the reduced frequency on the brake solenoid. I don't think it would have an effect on it. I'm just not sure. The brake motor is internally wired so I can't separate the brake from the motor windings.

Created Date: March 03,2003

Created by: ericn

My primary concern is the reduced frequency on the brake solenoid. I don't think it would have an effect on it. I'm just not sure. The brake motor is internally wired so I can't separate the brake from the motor windings

I feel this is a not a good idea. If you look at any motor catalog, they usually say something like "If brake motors are to be used with any electronic control, soft start, inverter or vector, etc., then brake must be externally connected " (quote from a Baldor catalog). The point being is simply that the brake may not fully disengage and the disc will drag.

I don't know why they connect these smaller motors internally... How hard is it to connect 2 wires in the motor junction box? In the cases where I have used these "internally connected " brake motors with a VFD, I always disassemble them and move the brake wires out to the terminal box (and cap off the "internal " wires). It's not really that difficult.

Created Date: March 03,2003

Created by: EricM

I currently have a 480V/1HP brake motor on a conveyor/transfer car. 1000# pallets roll down our assembly line and onto this transfer car. The transfer car runs on tracks to different work stations. The brake motor is ok. We have a proximity switch set about four inches before the point we want the car to stop. The transfer car stops within one inch either way of where we need it. We are changing our process so this won't be within spec anymore. I was wondering if I could use a GS2 drive. If I put that prox switch exactly where I want the transfer car to stop and then put a another prox switch 6 inches before that one. When the car gets to that first prox I could have the motor say slow down to half speed. This would give me a more precise stop. Would this cause problems with the brake part of the motor? Will I need to put a motor without a brake on the car?