DC Motor Control

[TonysControls]

Hey there, I just have a motor related question. I am using a 90V DC motor (https://www.motion.com/products/sku/03889770) and am controlling it with a VSD (https://bardac.com/wp-content/uploa...k340xri_680xri_1220xri_product_manual_v15.pdf). I am using relays to control the polarity reverse on this motor but intermittently the polarity will not reverse. I have tried re wiring this and it still does the same. This is only on 1 of the 3 stands that are in production but I have yet to figure out why even though the correct relays are coming on to switch the polarity it still is sometimes not reversing. Any help would be greatly appreciated!

 

[GaryS]

The DC drive is a 4 Quadrant drive that means it capable of running in reverse
It is also capable of running in regen mode so your relays to reverse the direction are unnecessary . Normally on these types of drives you invert the speed reference to reverse the direction.
The transition from forward to reverse is bump less it just ramps down to zero and then accelerates in the other direction
I would check to make sure that your speed reference is not going negative when you lower the speed reference to zero that will cause the drive to reverse the output to the motor