Has anyone out there experienced excessive noise from a Delaware power unit? These are 40hp submersible units, 208 volt, soft start, and they are LOUD! Excessive humming, almost sounds like a transformer hum. Tanks don't vibrate, there is rubber isolation under the power units and there is a rubber isolation pad between the pistons and car platform. You can hear these power units 5 floors up and the machineroom/shaft is solid concrete and block. Has anyone found that the air bladder style mufflers work any better than a standard muffler? These units are loud right from the get go, even when bumping cars up using hoistway access.

Looks like these are the only two noisy units in the whole country?

I'd resize the valve. It's most likely bypassing because it wasn't setup correctly.

VTech
Any chance the feedline is transmitting that song through the wall or ceiling and into the bldg. due to poor isolation? Are they new const./mod units, or new to you from another company?

Another company installed these new (tore out perfectly good basement Otis tractions) and now they are no longer in business. The piping is isolated pretty good (fire caulk at wall penetrations) and the power units do sit on rubber isolation pads. I was called in for my opinion and to see what we could do. I am going to use Otis style thick platen plate isolation pads, air bladder mufflers, and isolation couplers to see if we can make it better (it should), but I still think it's internal to the power units themselves. They just have a hum to them like a damn transformer hum as soon as they start up. Even when just bumping them up on hoistway access they are LOUD.

is one motor winding wired backwards?

The contractor who put this stuff in may be out of business, but according to their web site Delaware elevator is in business and still selling to the general public...(Non-Proprietary)

Here's some specs for their submersiable unit.

http://delawareelevator.com/manufacturing/power-units/submersible.cfm

And their contact page for manufactureing for technical assistance.

http://delawareelevator.com/manufacturing/contact.cfm

Suggestion...Check amperes on each phase in Wye and Delta configurations. GreenPants may be on to something.