Hydraulic pulsing

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I have a two stop hydraulic submersible originally installed by Mowery elevator in Florida. It is very standard equipment, Maxton uc-4, alweiler pump, Transamerica motor. About 15 years old. Was running fine for the years we've had it on service.

Starting in the last month, it has developed a vibration or pulsing in the elevator as it runs up, very noticeable sound and feel. Down is perfect and up is stable and easily adjustable with the valve. Runs just like it should except for the pulsing.

We started by changing the packing and checking rails like is common. no change. then moved on to the machine room. Changed the pump, motor, muffler, rebuilt the valve, none has changed the period or loudness of the noise.

I can shut off the gate valve in the machine room and run the pump without the valve coils and hear the same sound .

I'm at a loss. New motor, pump, muffler... what else is there?

-- norm swan (norm@nospam.com), December 02, 2004


Check starter contacts. You could be losing power to the motor. Check for voltage drop while pump is running.

-- Lowell (Lowferg@aol.com), December 02, 2004.

Hi There, check for a pin hole air leak, had a dry type power unit and changed everything and it ended up being a pin hole leak in the up section fittings. Jim

-- Jim (elevator555@hotmail.com), December 02, 2004.

did you check or change the coupling on the pump motor connection

-- rovingmutt (rdl713@hotmail.com), December 02, 2004.

With the car running up in leveling mode, check for aeration of the oil in the tank. A loose or bad fitting on the discharge side of the valve can suck air. If these air bubbles get thru the pump inlet, they cause cavitation on the screw of the pump.

-- Kirk Muller (kmuller@maxtonvalve.com), December 03, 2004.

Had the same symptoms on a schindler hydraulic- turned out that the ram was out of plumb and vibrating on the up-greased it and stopped it to a more acceptable whine,-hope this may help-course you could always sell customer a complete refurb, good luck.....

-- kvs (groucho9@aol.com), December 03, 2004.

norm had same problem on a mowery its a good one i done away with the phase monitor that was homemade and put a r.p.relay also look at prints all proxy switch are wired n.c. if one is going bad it will open/close open/close sounds crazy i know but check into the switches they are hard one to find let us know what you find

-- mark (mww6673@yahoo.com), December 05, 2004.

Do you have solid pipe or flexible pipe between RAM and pump,if flexible could be pipe wall is expandig when lift is travelling UP!

-- PAUL SCHOFIELD (louisems@bigpond.net.au), February 05, 2005.

I want to follow up with everyone.

Got a solution to the problem and it makes sense.

When the team changed the motor they changed the windings but reused the stator. the laminations were bad in a couple of spots causing the hum and current surge.

Changed the motor and it runs smooth.


Thanks for all the suggestions


-- norm swan (norm@nospam.com), February 10, 2005.

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