I am using ABB make VFD to run my 215HP motor for Blower application. I am giving reference speed signal (4-20mA) from controller to control air flow. Is there any chances to over speeding of the motor by reference signal although I have set the frequency limit in the VFD module.

 

Shouldn't be. Every ABB drive I'm familiar with respects the limits regardless of any other factors. In fact, typically the min and max of the analog signal will be scaled to correspond to the motor min and max rpm.

Not sure what will happen if you send a signal larger than the nominal max, IOW if your input is configured for 20ma max and you send 21ma, but I'm pretty sure if it results in a speed or frequency higher than the max set in the "Limits" group, it will be ignored (if the drive even recognizes signal in excess of the configured signal max in the first place).

 

Thanks Steve