Single VFD and multiple motors

[ptonsparky]

We have used single VFDs to control several motors on a conveyor in the past. All motors were the same hp, rpm, and I believe mfg. Worked great.

Another customer has a process with several different HP motors that he wants to vary the speed on. All would be in the range of 1750 rpm. Will the 3/4 hp react differently than say the 5 hp or the 3 hp when all are controlled by a single drive? Will it affect the drive adversely?

Most likely we will use several different drives with a 4-20ma loop but I am curious.

 

[weressl]

We have used single VFDs to control several motors on a conveyor in the past. All motors were the same hp, rpm, and I believe mfg. Worked great.

Another customer has a process with several different HP motors that he wants to vary the speed on. All would be in the range of 1750 rpm. Will the 3/4 hp react differently than say the 5 hp or the 3 hp when all are controlled by a single drive? Will it affect the drive adversely?

Most likely we will use several different drives with a 4-20ma loop but I am curious.

Would not work with different HP on the same drive.

I would be very cautious to utilize one drive for multiple, identical motors on a common mechanical coupling. There is an inherent difference in the electrical characteristics of each motor that could cause the motors unevenly loaded. Under extreme circumstances some of the motros may even be overloaded. With different manufacturers the problem will be even more likely, even though the HP and RPM are the 'same'.

These applications call for synchro or servo drive. Individual ASD's with feedback control may work, but it could cause them unevenly loaded too.

 

[ptonsparky]

Thank you,

I should clarify that each motor serves only one section of a conveyor system. They are not mechanically coupled to another section.

The system in question with different HP motors are not directly coupled either. They are augers, drags, legs, and air locks all of different hp depending on length etc.