Today I broke.....

[puffernutter]

My son's mains powered but diesel heated pressure washer!

It normally gives out smoke from the diesel heater, however whilst using it, smoke was coming from the other end - so I need more Lucas smoke!

I had to finish the job using my petrol powered washer, then had a chance to look at the damage!

It looks like the connections to the on/off switch (output side have melted!) I cannot find any details on the switch and it looks like it could have had a thermal trip on it, but at 5A it is far too low and never been wired it. Also it is a simple on/off and not zero volts release. I also suspect it is not original!

So, what to do?

I don't think there is any benefit to a no-volt release, so a simple switch rated at 15A or above. Water resistant is required but rocker, rotary or push?

Also if in use for a while it regularly blows 13A fuses (in the plug top) any benefit to having an accessiblle re settable trip?

Any thoughts from those of you more experienced than myself?

Pictures of the damage, below!

Cheers

Peter

Top of switch

Output from switch. I don't think the far right was used (thermal trip?) You can see the melted neutral to the bottom of the picture. Live was fine!

Bottom of switch with the protective cover removed.

 

[angellonewolf]

was it pulling more amps than the switch is rated for seams like theres a lot of damage and a bit of rust in there as well all the contacts look burn as well could have been arcing for ages

 

[puffernutter]

I'd not looked at the internals before. There are no details for what it was rated for. It runs off a 13A plug (which it does blow from time to time!) so a 20A switch should be adequate.

Cheers

Peter

 

[angellonewolf]

not the only person but @brightspark might add some thing to this possably

 

[carbon]

Would have thought 20A switch with 15A resettable trip would be suitable. If keeps blowing fuse check value of the motor capacitor if possible. Blowing fuses can also be a symptom of a leaking unloader valve if the machine shuts down when the trigger is released

 

[Maker]

Blowing fuses can also be a symptom of a leaking unloader valve

I thought it was just a symptom of too small a fuse.

 

[WorkshopChris]

It looks like the connections to the on/off switch (output side have melted!) I cannot find any details on the switch and it looks like it could have had a thermal trip on it, but at 5A it is far too low and never been wired it. Also it is a simple on/off and not zero volts release. I also suspect it is not original!

Yes this has a current operated trip fitted, looks like the contact have burn once before and someone has moved the wires over to the unused set, so its had its day.
It would be an expensive bit of kit to replace so probably worth fitting something decent to protect the motor in case of thermal overload.

EDIT> https://uk.rs-online.com/web/p/motor-protection-circuit-breakers/3313668/

 

[puffernutter]

@WorkshopChris, thanks. Looks the part.

I was looking at a cheaper option :-) https://www.ebay.co.uk/itm/273038260296?clk_rvr_id=1529354549516&rmvSB=true :-)

With a separate on/off switch!

 

[angellonewolf]

https://www.ebay.co.uk/sch/i.html?_nkw=V+Motor+Protection+Switch&_in_kw=1&_ex_kw=&_sacat=0&_udlo=&_udhi=&_ftrt=901&_ftrv=1&_sabdlo=&_sabdhi=&_samilow=&_samihi=&_sadis=15&_stpos=&_sargn=-1&saslc=1&_salic=3&_sop=12&_dmd=1&_ipg=50&_fosrp=1

ebay same £20 ish

just cheak the specs to make sure i only put motor protection the title

 

[carbon]

I was looking at a cheaper option :-) https://www.ebay.co.uk/itm/273038260296?clk_rvr_id=1529354549516&rmvSB=true :-)

See those sort of overloads in a few hot washers fitted as standard

https://www.ebay.co.uk/sch/i.html?_...lc=1&_salic=3&_sop=12&_dmd=1&_ipg=50&_fosrp=1

ebay same £20 ish

Seems the low current ones are about £20 when current gets up to 16A price increases to around £50 or above

 

[WorkshopChris]

@WorkshopChris, thanks. Looks the part.

I was looking at a cheaper option :-) https://www.ebay.co.uk/itm/273038260296?clk_rvr_id=1529354549516&rmvSB=true :-)

With a separate on/off switch!

Should do the job. (might be a little on the high side ).

 

[puffernutter]

https://www.amazon.co.uk/DealMux-DZ...3&sr=1-1&keywords=motor+protection+switch+16A

Thoughts?

Cheers

Peter

 

[Allthegearnoidea]

I like the idea of this thread. Today I broke two machine mart carbide boring bars and 1 indexable boring bar insert. I was trying to machine the splines of a sprocket. Turns out the sprocket was really hard. A file won’t even touch it.

Chris

 

[Seadog]

Inserts don't like interrupted cuts. Brazed carbide is more tolerant. Or, you could try and plunge in at the root of the spline. It depends how much you're trying to take out I guess.

 

[Turbo]

I used to service & repair pressure washers & I've fitted dozens of those switches. If it was fitted originally you should fit the same type of switch again. The resettable thermal overload you linked to will not provide the same protection.

That type of switch is designed for use for 3 phase & for the overload to work properly you need a load across all 3 sets of contacts. So when you are using it on single phase you have to loop the live around & run it through the switch twice. That switch doesn't look to have had that done.

To wire it you do this -
Live in to terminal 1
Connect a piece of brown wire from terminal 2 to terminal 3
Motor live to terminal 4
Neutral in to terminal 5
Motor in to terminal 6

You mentioned that it sometimes blows 13a fuses. Quite a few of those washers have 2.2kw / 3HP motors so they really should be running on a 16A supply. If you are using an extension lead it will need to be at least 2.5mm2 cable, fully unwound, ie treat it as a welder.

Looking at that switch it has been overheating, likely caused by inadequate power supply. If the overload switch was incorrectly wired it wasn't doing its job to protect the motor by tripping out when the current got too high, so it eventually melted the switch. You will be lucky if the motor hasn't been damaged!

If you have room you can fit a motor start switch like this.

https://www.ebay.co.uk/itm/On-Off-S...747950&hash=item5d791ac1f5:g:zh8AAOSwH2VaO5l9

This one won't work for you as it's for 380v but that type can be a lot cheaper & more reliable.

Search for 'Motor Magnetic Starter' or 'DOL starter'

https://www.ebay.co.uk/itm/DIRECT-O...hash=item3b033e66b0:m:mh1Mj29y0jx0jM1bxbZQ9cw

 

[puffernutter]

All good advice. Thanks. I'm not convinced it was original and the third contact looks like it was for the thermal trip, which may be a maximum of 5A (probably why it wasn't used)!

Cheers

Peter

 

[carbon]

Usually use all three contacts, two for live and one for neutral. I the past have seen a 5 amp switch supplying a 13A motor but all three contacts were wired in parallel for the live to spread the load out and the neutral wasn’t switched

 

[Fintray]

This has likely been caused by a poor connection either in the terminal block or if the cable has been crimped poorly, a point of higher resistance causes heating at that point which can lead to arcing and eventual breakdown of the connection.

 

[knighty]

I've fixed a few with similar faults, there's lots of vibration so an iffy connecting bruns up pretty quickly

while you're fixing it... check the burner nozzle, chances are the filter built into the back of the nozzle is blocked, they're only a 3 or 4 quid so worth replacing it

if you check the old nozzle it should have to numbers, something like 1.25 60 - which is 1.25kg of fuel per hour and a 60' burner angle (the angle of the cone shame the flame comes out in) - 2 seconds on google and you should find a load of places to buy them for :-)

if you can... fit a filter in the fuel line to the burner, one of those cheap paper ones is enough... much easier to change one of those than strip the thing down again :-)

 

[puffernutter]

This has likely been caused by a poor connection either in the terminal block or if the cable has been crimped poorly, a point of higher resistance causes heating at that point which can lead to arcing and eventual breakdown of the connection.

Interesting, my day job is railway signalling and we use very well designed, manufactured and tested relays (contact gap, force etc.) and we never use contact in parallel for managing current as even with our highly tested and produced relays, contacts will make or break at a slightly different time, so one contact will always make or break before the other and take the load.

This may not have a great effect here, but it's interesting nevertheless.

Cheers

Peter