Saturn_Europa
Senior Member
- Location
- Fishing Industry
- Occupation
- Electrician Limited License NC
Gentleman, I've got a head scratcher.
Its a Trane system with a large blower on the central unit. Its connected to 6 VAVs. Discharge pressure is usually 1.5 psi. It is currently 0.21.
Blower Fan Motor name plate:5 hp . 6.6 FLA. 1750 rpm.
VFD is putting out 60 Hrz but the motor is spinning visibly slower then usual. I am going to put a tach on it first thing tomorrow. One of the guys thought it was free wheeling but when you turn the VFD off it stops. Its just turning really slow. Probably 200-300 rpm. This is why my discharge pressure is so low.
The Hrz are maxed out but the vfd amperage is very low. 2.1 amp. I double checked with a clamp on amp meter and hertz and amps are spot on.
Has anyone seen anything like this before. The unit has been in operation for 2 years so its fairly new and just started acting up today.
I was thinking its the motor. But with a 3 phase induction motor if its bad, its bad and will through a breaker or OCPD, not just turn slower.
One thing I did not do is check volts on the motor side of the VFD. Volts on the line side are 480/277 and well balanced.
Its a Trane system with a large blower on the central unit. Its connected to 6 VAVs. Discharge pressure is usually 1.5 psi. It is currently 0.21.
Blower Fan Motor name plate:5 hp . 6.6 FLA. 1750 rpm.
VFD is putting out 60 Hrz but the motor is spinning visibly slower then usual. I am going to put a tach on it first thing tomorrow. One of the guys thought it was free wheeling but when you turn the VFD off it stops. Its just turning really slow. Probably 200-300 rpm. This is why my discharge pressure is so low.
The Hrz are maxed out but the vfd amperage is very low. 2.1 amp. I double checked with a clamp on amp meter and hertz and amps are spot on.
Has anyone seen anything like this before. The unit has been in operation for 2 years so its fairly new and just started acting up today.
I was thinking its the motor. But with a 3 phase induction motor if its bad, its bad and will through a breaker or OCPD, not just turn slower.
One thing I did not do is check volts on the motor side of the VFD. Volts on the line side are 480/277 and well balanced.