Changing Motor Speed


Thread Starter


Allen Bradley model 1336s installed in nsc-France made gill box (textile machine). This drive control to double speed (slow to high) main motor of machine. Motor speed accelerated by potentiometer that available on machines main electrical operating board. Since drive is old, after shift machine from one place to another place, we are facing this problem. main motor running normally slow to high. but, after change in to higher speed machines display showing 450
meters/minutes which is very high than our required speed 200 to 250
meter/minutes. We tried to reduce speed by given potentiometer but does not change the speed and running at constant speed ie 450 meters/minutes. We tried to check parameters but are password protected and in French language.

We ask your valuable comments on this matter.
I assume you have 2 potentiometers one for high speed, 1 for low speed and switch between speeds with a relay.

Typically on an older drive the potentiometer will have a Voltage like 0V at the CCW end and 10V at the CW end, As you rotate the pot clockwise it will go from 0 to 10V on the slider, this 0 - 10 V will show up on the drives setpoint input.

Check it does in both high and low speed mode.

If your High Speed pot breaks at the low end or the 0Volt connection is not made properly the slider will go to 10 Volts and obviously overspeed

send me an email rmatson at noram-eng dot com with a sketch of your wiring and I might see something.