kwired
Electron manager
- Location
- NE Nebraska
I agree and thought the same thing about the 152A observed at the motor shop. Certainly our motor service specialists could have missed something but our contact mentioned he was very impressed with the results from the winding tests performed at the shop. They have mentioned rewinding the motor as a possibility but that's probably a last resort for us right now. I tend to believe the motor was connected correctly at the motor shop based on conversations I've had with our contact. I have checked our connections here on site and know that Line connects to T1, T2 and T3 with other connections open for Slow and that Line connects to T6, T4 and T5 with T1, T2, and T3 shorted for High. At this moment I can't guarantee that the phasing is per the drawings at the motor junction box other than knowing that the fan turns in the correct direction in both Low and High, which I would think would be immediately disastrous for the motor if both Low and High phased with opposite rotations. The rotor had damage from the bearing failure and I am told the repair consisted of it being built up, turned down and balanced. The most perplexing thing, to me anyway, is that the motor operates below FLA while in Low. To my limited knowledge I'd think if there were a winding or mechanical problem within the motor the current draw would be proportional in both Low and High.
Thank you for all for the great responses. You're all helping me grease the rusty cogs in my old brain.
But mechanical load of the blower isn't 1:1 as speed changes. I don't know exactly how power factor and efficiency will change when speed changes on such a motor either - might not be same on high as it is on low, throwing your expectations off some as well.