Any idea why my new 13 amp pressure washer is tripping a 15 amp circuit?

[masterc]

I just got a Simoniz electric pressure washer.
It has a 13 amp motor.
I had it connected to an outlet in my garage which is on a 15 amp fused circuit. After running it for sometime and releasing the trigger, it blows the fuse when I start it up again, by squezzing the trigger.
I checked the circuit. There is nothing else running on it at the time. I have used this for my skill saw and a mitre saw in the past, without any problems (don't know their current draw)

I then plugged it into a circuit on my house, which is on breakers. Again same problem... trips the breaker.

I have tried a friends power washer, a Craftsman brand but also 13 amp motor. It runs no problem.

I think the motor on my new power washer may be the problem. It seams to draw too much current after it has idled for sometime.

Any ideas? Am I missing something really basic here???

 

[Anubis]

13 amps to run im guessing it pulls more then that to start

 

I'm no electrician, but maybe the motor is running at higher than 13 amps? Considering the thing was probably made in China, it could be that the description on the box differs from the actual motor in the washer.

 

[beer]

I'd probably return it to the store. There's a lot of circuitry involved, if some of the motor brushings are out of spec, to achieve a specific rpm of the motor will require more power drain, which seems like the case. I'd return it anyways, it seems set to die early anyways.

 

[Sundog]

Originally posted by: Anubis
13 amps to run im guessing it pulls more then that to start

That is what I would also think.

 

[Shockwave]

Originally posted by: Anubis
13 amps to run im guessing it pulls more then that to start

Yep

 

[LemonHead]

Go here for the answer. Good Site!

Pick the "Electrical" forum.

 

[db]

Frequently the circuit breakers trip at 80% which is 12 amps in your case.
And if the circuit is a long run, that cuts down the available amps too.

 

[beer]

Originally posted by: db
Frequently the circuit breakers trip at 80% which is 12 amps in your case.
And if the circuit is a long run, that cuts down the available amps too.

The electical resistivity of copper is something like .04 ohms/meter. It's negligable.

 

[XZeroII]

Look at the length of the cord you are using. Are you using an extension cord? A cheap one? That will definately cause problems.

 

[Howard]

Simplest answer: something else on that circuit is using current.

 

[Shockwave]

Some electric motors can pull somewhere around 3 or 4 TIMES the running current load at startup. This is probably why your blowing your fuse, in the transition between no load / load its pulling a helluva lot more current to keep running.

 

[masterc]

Thanks for the replies...

I have the unit plugged in directly... no extension cord.
It is the only thing running on that circuit.

I believe the start up surge and the fuse rating at 80% is the problem. (Maybe i'll stick a penny in the fuse base ;-)

Looks like i'll return it. Hopefully I still can. I used it once , it's not even two weeks...

OH yeah... It's made in China

 

[3chordcharlie]

Originally posted by: Howard
Simplest answer: something else on that circuit is using current.

Most fuses can handle a start surge of at least some magnitude; your 12-amp vaccuum never blows a fuse right? And I suspect your skillsaw has a higher startup current than a properly functioning power washer, though I can't be sure.

The thing pulling the extra power could be the extension cord that is running from your garage to your driveway (apologies if I'm assuming too much here). If this isn't the case, it's probably something along the lines of what others are suggesting - the motor is simply out of spec. Crappy Tire, or wherever you got it should be pretty good about an exchange if you have the receipt. I have a 13amp simoniz washer which has had no problems.

 

[Sukhoi]

Originally posted by: Shockwave
Some electric motors can pull somewhere around 3 or 4 TIMES the running current load at startup. This is probably why your blowing your fuse, in the transition between no load / load its pulling a helluva lot more current to keep running.

Yep, you're gonna need a 20 amp circuit for that power washer.

 

[beer]

Originally posted by: Sukhoi

Originally posted by: Shockwave
Some electric motors can pull somewhere around 3 or 4 TIMES the running current load at startup. This is probably why your blowing your fuse, in the transition between no load / load its pulling a helluva lot more current to keep running.

Yep, you're gonna need a 20 amp circuit for that power washer.

Isn't your standard 120 VAC 3 prong outlet supposed to be 20A anyways?

 

[Squisher]

Something is getting overly hot(bearings most likely) with use and when you restart there is too big of a drag on the motor.

Return it.

 

[TechnoKid]

Originally posted by: beer

Originally posted by: Sukhoi

Originally posted by: Shockwave
Some electric motors can pull somewhere around 3 or 4 TIMES the running current load at startup. This is probably why your blowing your fuse, in the transition between no load / load its pulling a helluva lot more current to keep running.

Yep, you're gonna need a 20 amp circuit for that power washer.

Isn't your standard 120 VAC 3 prong outlet supposed to be 20A anyways?

bedrooms that have 3-5 outlets are on a 15amp breaker, at least that's what i notice about my house, built about 5 years ago. Most of the GFCI are on 20amp breakers. I guess it really depends on what's expected to be connected to that particular circuit, and how many outlets are on the circuit. The outlet for the fridge is on a 20amp, as is the 120V lines for the washer/dryer (the 220 lines for an electric dryer are on a 30amp i think; i got a gas dryer).

 

[Shockwave]

Originally posted by: beer

Originally posted by: Sukhoi

Originally posted by: Shockwave
Some electric motors can pull somewhere around 3 or 4 TIMES the running current load at startup. This is probably why your blowing your fuse, in the transition between no load / load its pulling a helluva lot more current to keep running.

Yep, you're gonna need a 20 amp circuit for that power washer.

Isn't your standard 120 VAC 3 prong outlet supposed to be 20A anyways?

It really depends on they wire it. Also, most outlets are shared. The old ones in my garage where shared with the ones in out sunroom. We had a TV the kids watched there, along with a space heater this winter. I could run the radio in the garage and that was it. Turn on ANYTHING else (Hair dryer, drill, saw etc) and the breaker would pop.
Course, now with 2 30 amp dedicated, I have no problems

So, it could be his outlets arent dedicated on the garage. That could be it too.

 

[Iron Woode]

I say try a fusatron first. That should allow the motor to spin up without overloading the circuit. Ususally a 3sec delay as the start up is usually fast. If that fails then something else is wrong.

Does it have a current info sticker or instruction manual? Maybe that could be helpful?

 

[LordMorpheus]

Originally posted by: Anubis
13 amps to run im guessing it pulls more then that to start

Bingo.

When a motor starts, there is virtually no resistance and it will pull a boatload of current (think, lights dim when you turn a fan on, but go normal once it is up to speed).

Once the coils in the motor starts turning, they generate a back current, or a potential that is resisting the movement of the motor. In a frictionless system, a motor would take zero amps to operate in a no-load condition. So when you turn it on, you might be drawing30 amps for a split second, certainly more than 2 amps over the operating amperage.

don't return it, its your house's fault it isn't working. Find a 30 or 40 amp outlet and run an extension cord from there.

Or swap it for a smaller washer that doesn't need so much current.

Or build an inductive resitor, use it to start the pressure washer then take it out of the ciruit. Take a few bars of rebar and wrap one of the wires (insulated) around it a bunch of times. It will create resistance directly proportional to the current running through it. It should stop the breaker, and with a few normal 120VAC switches, you can take it out of the circuit easily once everything is running fine.

It'd be fun, but a pain in the ass after you had to use it a few times. I say buy a bigger breaker/fuse or use a different outlet.

 

[Squisher]

Did any of you guys read this part in the original post?

Originally posted by: masterc
After running it for sometime and releasing the trigger, it blows the fuse when I start it up again, by squezzing the trigger.

The breaker trips after it has run for a while. I stand by my post that something is getting hot, probably the bearings and that the OP should return it.

 

[Shockwave]

Originally posted by: Squisher
Did any of you guys read this part in the original post?

Originally posted by: masterc
After running it for sometime and releasing the trigger, it blows the fuse when I start it up again, by squezzing the trigger.

The breaker trips after it has run for a while. I stand by my post that something is getting hot, probably the bearings and that the OP should return it.

Yes. Hence me saying going from no load / load. It isnt always whether or not the motor is on, but the load the motor has. The current draw is mostly due to the load. So, if he runs it, then releases the trigger it goes from a load to no load. When he pulls the trigger again it goes from no load to load.

Thats what I bet is happening. Could be wrong though. If its under warrenty, I'd return it either way.

 

[Eli]

Originally posted by: Squisher
Did any of you guys read this part in the original post?

Originally posted by: masterc
After running it for sometime and releasing the trigger, it blows the fuse when I start it up again, by squezzing the trigger.

The breaker trips after it has run for a while. I stand by my post that something is getting hot, probably the bearings and that the OP should return it.

No. You don't understand.

As others have said, electric motors can take up to TEN times their rated current as they spin up to speed. That is an extreme case, but it is entirely possible. 3-4 is much more reasonable, as Shockwave stated.

My guess is that since 13A is so close to the circuits max rating, you warm it up, so to speak.. and when you cycle the motor once again, it blows.

Don't take it back. It is not broken.

Although, the bit about your neighbors pressure washer does raise an eyebrow. Are you SURE that *everything* is the same when you try and duplicate the problem?

 

[morkinva]

Did you try messin with the pressure adjustment knob?