Washing machine pump speed control, voltage drop down.

[no_spark]

I have a combo washing/drying machine. It uses cold water to remove moisture in the air while drying. A universal complaint on these is the loud drone of the water pump every 30 seconds or so.

If possible I would like to quiet the pump. Using variacs I have been able to slow down my household fans from the 1920's. Would this method work/be ideal on a water pump?

The machine will throw an OE (tub not drained) error if more than 10 minutes are required to empty the tub. Right now the pump can drain the full tub in only a minute, so I think there could be room to slow things down. There is room in the washer cabinet for a panel mount variable transformer, if this worked I could adjust the speed once in for enough power while still being quiet.

I found a variac for sale on ebay. I am not quite sure what specs I would need. The washing motor is running on 240v AC from the main PWB?

Wiring Diagram:



Pump Motor:



Pump:



Variac:




Power input:

I have installed this washer where the oven once was. The wall outlet located close is a 240V circuit. The washer runs on regular 120V power. When the heater is on the washer draws 2000 watts so I am close to the limit of my 120v circuit. Can I add a drop down transformer to power this that would simply plug into the wall outlet > convert to 120 > and have an outlet to add this washer to?

From what I have read I am on a NEMA 10 -50 which is obsolete and possibly dangerous? Also, I would need to change a breaker to 15a? I am looking for a safe plug-in only solution without modifications as I do not own my apartment.

Oven plug:



Step down transformer:

 

[BradtheRad]

A variac is just the thing to slow pump speed, assuming it really would reduce noise.

* Just as an experiment I would try putting a resistive load in series with the pump. Say, a space heater. Maybe a high W bulb (or a few low W in parallel). Enough resistance to drop the pump to 70 or 80 percent of normal power. See if noise level drops.

* Noise is transferred by rigid mounts. Have you tried loosening the mounting bolts, installing foam to dampen vibration, etc.?

* It's essential to measure pump current. The variac costs $30 (+$17 shipping) and it's rated 0.7A. The diagram quotes 162-176 ohms for the pump, which implies it draws 1.4A. This means you'll need to severely cut down power to the pump, for the variac to survive.

 

[c_mitra]

I cannot guess the drain water motor power use but it may be around 50-100W. It may be possible to slow down using a series resistor (like a light bulb; as suggested in #2) but please check first whether the motor mount is good enough to cut down the noise. The drone sound you mentioned is perhaps high frequency (>5000Hz) but the vibrations can still be felt by touch. It may be better to kill the "effect" rather than attacking the "cause" in this case.