MOTOR UPGRADE: WHAT CHANGES?

[ash90]

Hi, I am upgrading an existing 3 hp motor with a 5 hp motor. I have an old Reliance vfd controller. I'm just wondering what changes will I have to make due to the motor change? I couldn't really find anything in the vfd programming manual.

any help is appreciated. Thanks!

 

[jraef]

Uh, is the VFD rated for 5HP? If not, the rest is moot.

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376

 

[macmil]

from a mechanical perspective, what's the load and drive system ? A 5 hp motor will have 60% approx more torque~~ can the drive system take this ? or will you run into other problems ? i.e. gear box ; shafts; belts ?

 

[ash90]

Thanks for the replies:

Yes, the VFD is rated for 5 hp.
The drive system can handle the extra torque, actually that's why it was upgraded.

I'm more worried about the electrical stuff. Mechanically it seems to be in spec.

 

[jraef]

Well for one, you will need to reprogram the motor parameters, i.e. the FLA, # of poles, etc. If it is a Vector drive, you will also need to tune the drive to the new motor. Most vector drives now have an auto-tune feature that works pretty well, but you didn't state the age or model of your Reliance drive.

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376

 

[dpc]

Normally, you'd have to be concerned about the feeder to the motor, but at this size, it was probably already #12 AWG which will be fine for the 5 hp motor.

You may need to adjust the current limits set in the VFD.

 

[itsmoked]

#12 AWG for a 5HP motor? Seems small off hand to me.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

Depends on the voltage

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376

 

[ash90]

575V; Old OLD reliance controller..I can't even find the model online to look at the manual. I guess I'll change the current limits first off. The controller max rating is 5 hp. Scrolling through the settings and not having access to the manual, I can only see thermal overload setting.

thanks everyone.

 

[jraef]

On an old OLD drive that may be all you have available to change.

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376