HI All,

We have one Aluminum CAN printing machine which is driven by 100HP DC Drive and motor.This was a six color printer and was upgraded to 8 color last week. Since then amps of the motor is very high. it was drawing 125Amps at 1500 CPM and after upgrade we are able to run at 600CPM at 180Amps which is full load for Drive (motor full load is 160Amps). We already changed motor but same amps is drawn. We have similar machine running on other line with 140Amps at 1500 CPM (Cans per minute). To prove machine is not the problem we decided to feed the motor power from the running machine panel and amps went down to normal. We checked voltage and it is 315VDC with 140Amps at 1500 CPM.

What could be the problem of Drive.
We are using Reliance DC Drive Flex Pak 3000. Model # 100FN4021

Thanks & regards,

Shree

 

Check your field current. Is it the same from each drive? Is it set per motor nameplate?

 

> Check your field current. Is it the
> same from each drive? Is it set per
> motor nameplate?

Thanks for your reply.
Yes. Field voltage for motor is 300VDC and field voltage from drive (both drives) while at speed is 296VDC. No field weakening used and both drive is using standard field power supply.

Thanks and regards,

Shree

 

Shree... I suggest you perform a simple torque-bar test to determine if there is significant (qualitatively) torque difference between the two machines!

Regards, Phil Corso

 

Try to measure field current, instead of voltage - is there any external resistance in the field circuits? Same for both motor circuits?