Washing machine water pump wiring

[HenryBenry]

Hi all...first post here. Can any electronics genius give a total amateur some advice on wiring up an old washing machine pump? It pumped out the waste water. I think I could work from a circuit diagram if I could find one.

I have got it to run since pulling it out of the old washing machine, but want to check I am doing it properly by fusing it and so on. It is 240v but wires to it look very skinny. I used the original plug from the machine which has some sort of copper coil on the back and thin wires connection, and that got it running.

Writing on the pump say this.

1 KEBS 116/065A CL. 115 093/ 17 19:54 220-240v 50hz 0.19A 25W 160029518.02

Any help would be much appreciated.

 

[wwfeldman]

1 KEBS 116/065A CL. 115 093/ 17 19:54 220-240v 50hz 0.19A 25W 160029518.02

220-240v 50Hz 25W means it should be powered by 240V as you said

50 Hz means is expects 50 Hz AC - it will probably work at 60 Hz, but will spin faster

0.19 A means the current draw while operating is 0.19 A, which explains the skinny wires
at start up, it could draw 10 times that, but only for a short time, so skinny wires are (likely) not an issue

25W average power is 25W (this looks low to me - i would expect about 45 to 50 W)

don't know what KEBS is

please provide make and model of machine it came out of
what is the frequency of the power in your part of the world?

 

[HenryBenry]

Thanks for this!

It’s from a Hotpoint WDAL 8640 Aquarius 8 + 6kg A class

In the UK so we use 3 pin plugs at 240v

 

[betwixt]

I'm guessing this motor only has two wires. If that is the case, all you can do is supply 240V to them to make it turn and remove the voltage to make it stop.
The power rating is adequate at 25W as most machines have the pump fitted at the bottom of the drum where gravity does much of the work. All it has to do is push the water a short distance up the waste pipe then syphon action takes over.

Brian.

 

[FvM]

In the UK so we use 3 pin plugs at 240v

It's a good idea to connect the center pin (protective earth) to the motor chassis.

 

[HenryBenry]

Yes, it does just have 2 wires, and yes Brian it does seem to mechanically work like you say and use the gravity.

Earthing sounds a good idea.

In terms of a circuit:
-i’d like to add a switch of course. -Should I fuse it?
-And can I wire it straight from the plug, or should I use the original plug with the copper coil on the back? What is that anyway?

 

[wwfeldman]

a normal switch for 240V should do.

it never hurts to have a fuse or circuit breaker tin the line.
especially since its function is to protect the input side from the motor

since nominal draw is 0.19 A, turn on about 2 A, you want a 1/2 A (?) slow blow fuse
or a comparable circuit breaker.
check the ratings carefully, as it need to pass about 2A for 1/2 (?) second at turn on without opening

how big is the copper coil?
what is it connected to?
it may be a small inductor whose function would be to control the inrush current

 

[betwixt]

A photograph of this coil would be useful. I doubt it is needed but it's size and construction would give us a clue why it was there at all.

Brian.

 

[HenryBenry]

Photo of plug with copper coil

 

[HenryBenry]

Another closer picture of the back of the plug. Not great pic though

 

[HenryBenry]

The pump I want to wire up

 

[FvM]

O.K., the "coil" isn't mounted at the plug, it's at the other cable end. Looks like a RF choke, probably intended to suppress electrical noise from the motor (or motor inverter, if any).

It's of no use when you operate the pump. A fuse may be connected, however there's usually no pump motor fuse in the washing machine. If the motor coil is burned, it will blow the 16A mains fuse.

 

[HenryBenry]

I see, saying back of plug could be confusing.

This sounds simple enough now. Thanks.

There is another washing machine component i’d like to wire up as part of this same thing i’m making...

 

[HenryBenry]

It’s the heating element. More complicated to wire up i’m guessing? I don’t want the liquid to boil, just reach 20-30c

 

[betwixt]

The two outside tags are for the mains connection, the middle one (spot welded) is the Earth connection. It must be earthed for safety!
The gadget with the white plug is a thermostat, I just had to replace the one in my machine. Here's the catch, the heater is rated at 1700W so it draws about 7 Amps from the mains but the thermostat is rated at about 1/1000 amp so you can't just wire them in series, you need a control circuit.

It isn't impossible to do but before advising, may I ask what the purpose is? A high power controller may not be the best option if you only want to heat a small amount of liquid to a relatively low temperature. Think of it as trying to throttle back a jet engine to use it as a leaf blower.

Brian.

 

[HenryBenry]

The difference between series and control circuit i’d have to look up, but guessing it means such different range of amps is more difficult.

These are intended for a bicycle parts washer. It’s circulated degreasing fluid, from a reservoir up through a brush fitted tap into a sink. Guessing washing machine parts can handle that. I want to do it for cheap and make it relatively large, with the luxury of being heated. Roughly 4 litres liquid to heat. Not sure how many lites a washing machine uses. The machine it’s from did 20 degrees centigrade washing, so didn’t think it was too mad an idea.

 

[betwixt]

Not mad at all but there are some difficulties in regulating the temperature you need to be aware of. In a washing machine there is a closed environment so setting the temperature is fairly easy to do. Controlling the amount of heat from the element is tricky so rather than control how much heat, a washing machine will simply turn it on at full power then turn it off again periodically, repeating every few seconds. The shorter the 'on' bursts, the lower the overall temperature will be and the longer the bursts hotter it will be. Some controllers use the thermostat (it is actually a resistor that changes value with temperature) to decide how long the bursts should be, some just do it on a timer and hope for the best!

In an open environment like you propose, there are several options, none of them ideal but all do-able. Your heat demand is likely to change according to what you are washing because of the ambient temperature the liquid is passing through and because some of the parts will cool the liquid down due to their own thermal needs. Just turning the power on in timed bursts is unlikely to be successful because there is no feedback to cater for the changing heat loss. You could adjust it manually by altering the timing yourself but that might be tedious, especially if up to your elbows in chain grease. It is possible to use the thermostat to sense the temperature, compare it with a pre-set figure of your choice and use that to turn the power on and off.

The more technical solution is to use what we call "phase control", essentially like a light dimmer but with the heater instead of the lamp and the thermostat instead of the brightness control. It gives continuous regulation of the power passed to the heater to maintain a fixed liquid temperature. It doesn't completely turn the power on and off as such, it chops each AC mains cycle to make it longer or shorter. This method gives finer control but you would have to build some electronics to make it work.

Brian.

 

[BradtheRad]

Look at a thermostat from a water heater. I removed one and disassembled it in an effort to fix it. I found a bimetallic plate that carried full current to the heating element (as I recall). It was in direct contact with the metal tank. It opened and closed as the water temp ranged around 120^oF.

I jimmied with the plate's curvature. I guess I fixed it because no disasters occurred.

 

[betwixt]

There are two types of 'thermostat' used in machines like that. The type Brad refers to is typically a penny sized disc that is screwed to the outside surface, these are used as over temperature cut-outs, a back-up safety feature in case the main control fails.

The type used in post #14 isn't technically a thermostat although that's what most service manuals call it. It is actually a 'thermistor', a resistor that changes in value according to the temperature of its environment. Typically they have a value of around 10K at 20C and it drops to about 100 Ohms at 100C. Thermistor resistance can tell the temperature rather than just whether it is above or below trip point. On the controller board, the microprocessor will use the thermistor value to decide whether the heater should be switched on or not and it will control a relay or triac to connect the mains to the heater element.

Brian.