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Shop vac fuse bypass

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Serge 125

Hi all, I know that this was already posted but still I just wana make sure if it's ok to do this. My shop vac stopped working a few weeks ago and I saw this little thing that I know it's a fuse. As you can see in the pic it has melted so I know that I can't get one at Shop Vac they will say that I need a new motor. So looking at this I wondered why is it there? I think it's more of a money thing, when it breaks you get e new motor or vac pretty simple. If I need this part then why? There's a little fan at the top of the motor to keep it cool so I don't see why I would need a fuse there. I know someone here did bypass it on his Craftsman shop vac but mine is just about 3-5 years old. So any help with this is welcomed!!!




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That does not look like any fuse I have ever seen.
It looks a bit like a fragment of a crimped connector or a motor brush "pigtail" connection?

A picture of the motor, showing where that is from, would be very helpful.


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Most Helpful Member
rjen is right. Some better pictures are needed.

The shop vac motor may indeed have a thermal fuse, which will fail if the motor gets too hot. It's not there to make you buy a new shop vac - it's there to prevent the motor from bursting into flames. That could ruin your day AND burn down your house.

Can't say for sure from your picture if that's a thermal fuse, but it's clear something got way too hot.

Serge 125

Thanks for answering!! No it DOESN'T look like a fuse someone said it looked more like a pice of solder wire that acts like a thermal fuse so when it gets hot it melts as it did in the pic. I don't have the photo of the inside but will do tomorrow in the after noon. BTW I said that there was a little fan at the top of the motor, it SHOULD keep the motor "cool" and prevent not to overheat.



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Most Helpful Member
It looks like braided copper wire used to allow carbon motor "brushes" slide in their spring-loaded slot and maintain pressure against the armature. This part is either a fragment of the little pin that holds the braided copper to the carbon brush, or, is a crimped connector to attach the braided wire to the power supply pins (e.g. a spade connector).

Serge 125

Ok here's the pics!! Now the top one is that little fan that I say that it SHOULD keep the motor running at a normal temp. The next one where the "fuse" was boxed in. Yep I did mod it for now.



Serge 125

Well bypassed it up to now works without heating on top of the motor I check it with a laser temp probe and I get normal non plastic melting temp at top of the engin housing . So I think it's more of a money thing to get a new motor or a new shop vac, nothing for safety here.


Well-Known Member
That is a winding temp fuse, after considerable use they often fail due to intermittent stress over time.
Although a vac motor draws less current if partially or constantly operating almost blocked, the temperature of the motor goes way up due to lack of cooling.
Also Current is highest when operating with no hose plugged in for example.


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The stupid fuse is just that very stupid. Totally familiar with the stupid thing. The big problem is that it's thermally massive compared to the winding wire gauge and it's just friction fit. It's also made of some thermal alloy. In my case, the weld to the terminals and the wiring was really tight, so it easily breaks.. I should say the tiny wire to the massive terminal breaks first.

I was able to re-use it after fixing the wiring issue.

My new motor failed most immediately with one problem and then again with this thing.

I'm not sure what to replace it with. If I had a new one or got a new motor, I know what I would inititally do:

Inspect the wiring and fix that first.
Put some conducto-lube (expensive silver stuff) on the contacts.

The real design fault is no brush monitoring system. Once the brushes reach the end, the motor is shot. Inspecting the brushes is difficult too. That part is a relatively new addition to the motor/top assembly.

I have a model 500 from the 70's. I added clips to hold the top in place. It was designed as a Tipp-n-tell:, not a vacuum.
The center of gravity is such that a tug on the hose dumps the water because it tips and the lid falls off. I fixed that.

Hoover made better vacuums in the 1950's than they do now.
1. Attachments didn't rely on friction.
2. When you inserted the brush, the brush was lifted off the rug.
3. You could pick it up at the bottom.

Now they discontinue parts that wear MAKING you buy another. e.g. brushes.

The latest hoover I have, needs a few mods on it.

1. The attachment cover keeps flopping off. I did make a magnetic catch that makes it better, but it's not good enough.
2. The switch broke
3. The cord runs warm, it not flexible and the brush destroys the covering.
4. The two piece wands won't stay on the machine - fixed with real clips.
5. The bag cover won;t stay on. The bottom is fixed with added metal clips.
6. The top won;t latch. It will be fixed eventually the same way I fixed a Dirt Devil. Now it's a string and spring.
7. The bag cover is cracked. Fixed with tape. No longer available.
8. A large slam will break the brush height gizmo. To get the rubber wheels I had to order two parts and switch parts. You had a choice of rubber or hard plastic wheels. Put it down GENTLY!.
9. No lubercation on the brush height gizmo.
10. The cord sucks. I should replace it with a cord from a Fein multimaster.
11. No easy way to lug it.

I have a Eureka that's really nice, but the handle keeps falling. I have not completed the mod to fix it yet..
The latch is half mounted.


New Member

A few years ago I had a big 10 year old Shop Vac with a dead motor. I emailed them and said I was a homeowner not a contractor and that even though it was 10 years old I only used it a few times a year and it seemed like it should be heartier than that. I didn't ask for one, but a week later a new motor arrived via UPS with a note that said thanks for being a customer. It's worth a shot.

Serge 125

Thanks for all the answers!! Well like I said before I bypassed it and works like new. This vac was given to me from someone at work and the blower wheel was stripped at the centre but an easy fix for this, later the motor just stop working so fixed it up and running like new. Since this was given to me I'll fix her up again (when she breaks down someday) until I can't do anything for it. Again THANKS for all the help and replies!!!
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