Common Dc Bus

[dip04051978]

We were there for commissioning 110KW, 75KW, 55KW, 30KW, 30KW & 15KW With Individual Braking resistor on Cranes. All the drives are connected on common DC Bus. Now the problem faced is:

 

During Main Hoist running DBR of Cross Travel got heated / some times long travel DBR heated.

 

 

[marke]

Hello dip04051978

 

I would suggest that if you are able to, set the drive with the largest braking resistor to operate at the lowest voltage. This is usually a setting in the drive along the lines of Dynamic Braking threshold. If the biggest resistor operates first, it will prevent the small resistors from trying to stop the large motor.

 

Best regards,

[niallnz]

On common DC bus applications I would have thought that it is normal to only have one DBR, typically as part of the largest drive on the network. Depending on how much brake energy you want to disipate you may have an independant DBR. Some drive DBR's have the ability to control the DBR's in the other drives so that they are slaves to a master, and therefore share the braking energy between resistors, BUT the sizing of the brake choppers and resistors must be compatable for this option and is usually done when the brake energy is too much for one single chopper and resistor.

 

Cheers

Niallnz