stevie5150 said:
Hi! I have a chiller that's giving me problems. The compressor is 230 VAC and I have a 208 VAC service. I have the power stepped up with a 75 KVA transformer from 208 to 240. With the chiller off, I have about 246 volts phase to phase. When I power it up, the voltage drops to about 226. ..I have another chiller set up the same way. The voltage drops from about 246 to 243 when I power it up. I have checked all connections. Any input is appreciated. Thanks.
Some people are accused of one track minds dominated by ??X. Until I learn better, for performance of electrical systems, my minds eye lusts for Z.
Because of measurements provided here, evidence of higher upstream impedance, Z=(Et-Er)/I, and lower wattage, W=Er*Ir, (less mechanical friction) applies to Chiller #1 (the problem chiller), relatively to Chiller #2.
Assuming these stabilized measurements for Chiller #1 (the problem chiller):
Et=246vac, Er=226vac, Ir=107A
And these stabilized measurements for Chiller #2:
Et=246vac, Er=243vac, Ir=105A
If the actual measurements correctly show Z is higher for the problem chiller, perhaps the least obvious culprit is reactance between different cable lengths, ferrous raceways, shielded cable, odd-spacing gaps between phases, or different Xfmr's %Z.