Noisy Esco transfer switch

[Johnontheroad]

Like many others, I have replaced my potentially dangerous IOTA transfer switch with an Esco ES50M-65N. Works great, and it appears very rugged. But it also has a very loud AC hum. You can reduce this hum by turning AC off and on again, maybe a few times, until the relays in the switch latch in a non-humming way.

Although cycling the power works, I would prefer to eliminate the hum at the source. I understand the ES50M-65N relays use AC to energize the pedestal circuit, and this requires the relays use AC all the time, hence the hum.

Further, since I bought my switch two years ago, I think Esco introduced a new switch that does not use AC to energize pedestal power (NC relays instead of NO), hence no hum. Either that or they use DC to energize the relays. Anyone aware of this and know the Esco part number? I looked at their site but not quite sure which one it is.

Any other suggestions gratefully accepted...

== John

[DtBt]

I think you are refering to the LPT-50BRD switch from ESCO. It is quieter but only uses a single 3 pole relay as the source defaults to the generator. That is not a problem usually but in certain failure modes some say it is unsafe. I don't really know or have ever heard of any issues.
For me I too had a noisy original ESCO ES50M-65N switch. It seems the hum is transferred to the motor home and reverberates making for a annoying loud hum. I solved by backing the mounting surface with foam rubber that reduced it enough so one had to stand outside compartment to hear it. Be sure to cut all power before opening cover to access mounting screws.

[Jeff753]

Originally Posted by JohnCamelot

Like many others, I have replaced my potentially dangerous IOTA transfer switch with an Esco ES50M-65N. Works great, and it appears very rugged. But it also has a very loud AC hum. You can reduce this hum by turning AC off and on again, maybe a few times, until the relays in the switch latch in a non-humming way.



Although cycling the power works, I would prefer to eliminate the hum at the source. I understand the ES50M-65N relays use AC to energize the pedestal circuit, and this requires the relays use AC all the time, hence the hum.



Further, since I bought my switch two years ago, I think Esco introduced a new switch that does not use AC to energize pedestal power (NC relays instead of NO), hence no hum. Either that or they use DC to energize the relays. Anyone aware of this and know the Esco part number? I looked at their site but not quite sure which one it is.



Any other suggestions gratefully accepted...



== John

I reduced mine considerably by loosening the screws, blowing them out good with contact cleaner and compressed air and re tighten firmly.


Jeff
2001 Dynasty Regent tag axle
Cummins 350 8.3 ISC