Hotpoint Wd71 Tripping Rcd

[Curious]

The RCD has tripped a couple of times. By a process of elimination (or finger pointing) the washing machine is the culprit. The kitchen accessories circuit is now relegated to a separate RCBO to save the annoyance when trying things out and it trips!

As soon as the washing machine would want to start running the motor the RCD trips. By disconnecting the power plug to the motor all is fine, i.e. it starts up and after a few seconds reports E30 (i.e. there's a motor fault!). I've checked the brushes and these look fine (machine about 4.5 yrs old). Contacts on the armature all look OK - none raised, and spins freely. It wouldn't appear to be a direct short to earth, as the fuse is fine, nothing arcs when the power is applied.

Doing an insulation test between earth and each of the spade connectors on the motor (going from left to right as you stand at the front of the machine)....

1 - >999M (red wire)

2 - >999M (red wire)

3 - 0.03M (black wire)

4 - 0.02M (brown wire)

5 - 114M (blue wire)

6 - 110M (white wire)

7 - 0.02M (yellow wire)

All tests @ 500VDC

I've not attempted to dismantle the motor to have a look for any visible signs, of insulation breakdown within it. Does this sound like something which is an obvious cause to you? If so, could you let me know what I'm likely to need to replace? I've seen the link to the spares site, so aware of armature, brushes, TOC17 which seem to be around there, but there's also the windings surrounding the armature which I've not seen the spares for. I'm also a little confused by the motor label, which is blue, yet the spares site seems to imply this is an 800RPM motor, which the WD71 has a 1200RPM spin - unless I'm misunderstanding the spares site.

If taking the motor apart is required, what is the dismantling process to remove it and get to the parts required? Thanks in advance, and well earned congratulations on such a useful web site and forum.

[Whitegoodshelp (Andy)]

This model could have one of 2 motors fitted. After date code 61 they used a different motor and it is only available at great expense. The date code on a Hotpoint washing machine is the first 2 numbers of the serial number.

If yours has a blue label on, it may be the earlier type which can be repaired easily. Basically, if the carbon brushes slot into the sides and can be removed by pressing in a plastic tab, and the brush then slides out then it is the earlier (common) type. On these motors, the same armature fits 800 spin and 1200 spin washing machines (161498B)

It sounds like the armature is down to earth. Double check this by removing the carbon brushes and testing with your insulation meter because worn carbon brushes and the carbon dust they create can cause a short which disappears when the dust is blown out and the brushes removed. Put one probe on the motor casing and the other on the commutator (the copper segments) Make sure your probe touches only the armature.

If you get the 0.2 M Ohms reading then the armature is down to earth.

Take the probe off of the armature, but leave the other probe on the motor casing and touch each of the motor pins in turn. You should get no reading (down to earth) on any of them now. If you do, it's likely to be from the field coil, which is very rare.

To check if the TOC has blown,

Use continuity test, and test between the left tag that fits to the left carbon brush (usually a black wire) and one of the pins on the motor connector. Do the same for the right carbon brush wire (usually a yellow wire) You should get a continuity reading between both these wires and a pin on the motor. If you only get one, the TOC has gone too.

The motor comes of easily. There's also only 2 bolts to undo and the motor end frame comes off. Mark the casing and field coil to assist realignment when reassembling.

Take the end frame only off (brushes should be out too) and then before sliding the old armature out, remove (unscrew - normal thread) the tacho magnet from the end of the armature. Put this magnet onto the new armature (in other words swap them over)

The old armature should slide out and the new slide in easily. If you have trouble getting the old one out then with the tacho magnet taken off, use a punch to knock it out.

Before refitting the motor, do another insulation test to make sure you haven't trapped any wires which would short against the casing.

Washing machine tripping electrics - help article

[Curious]

Thanks. My serial number starts 71 so it looks like I could be in for an expensive fix!

I've taken the motor apart. The armature and TOC are fine. With the brushes and armature removed, there is still a resistance of 22k to the chassis of the motor. I looked at the crimp connectors for the windings to see if those could have rubbed against the plastic insulation, but they look fine. I have also made sure there is no visible sign on any carbon "dust" which could have come from the brushes and created a short between any of the connections along to the chassis.

The windings themselves don't show any visible signs of problems, e.g. any sign of rubbing or arcing, etc. Something could be wrong underneath them. Where the white plastic isolation membrane is visible, it looks to be OK and intact. Continuity is OK on all parts, just something in the field coils which is going to earth. I could disconnect and test each of the coils to see which is the offending one, but I doubt this achieving anything as I expect it will be a replace all part.

The motor doesn't have the plastic clips for the brushes, it's also the type with a digital tacho on it, and sounds from your info as though it is the more expensive one. Do you know how much this is likely to be?

I suppose I could contact Hotpoint as it's less than 5 years old, on the basis of the parts being covered. Am I correct to think that they won't supply the parts without having them fitted by one of their engineers (and charging)?

[Whitegoodshelp (Andy)]

Yes, whichever motor you have, if it's the field coil, you can only buy a new complete motor.

I would put the motor back together and call in Hotpoint under the 5 year parts guarantee as it seems like it will need a new motor. They should fit a brand new motor for you at roughly £90.

( Related: I have a 5 year parts guarantee - should I use it? )