triping circuit breaker

Wow.

Read all the posts and am not seeing the running voltage. The 80+ amps disturbs me if this is a single phase motor because 80+ amps is a lot to manage for a single phase enviorement in any case.

A 15HP should be 3 phase things. 480 volts and if just 240 or so the wire size should be up there. For the temperature mentioned on the news today the wire size should be at least 2 sizes above code and more so if the runs are long. 100' or more.

So is the pump in a deep well or on the surface? What are the original readings when installed? I don't know how often or how much the pump is used but it should have a regular maintenance schedule to including pulling it out of the well if it is in one and maiking sure all is well. Beaings do go bad. Connections and contacts do need to be checked yearly.

Besides all the connection things mentioned, hopefully all the wiring is Copper and not Aluminum.

Is the breaker a motor type and the correct one for the use?

Bob AZ 106 right now.

Child labor laws? Kid's job---Conductor!

LMAO

NO, By doing so you would only be attacking the symptom of a problem, nothte problem.

Essentially no. By doing so you effectively change the trip rating of the breakers (all of them), if it changes to the point where the trip rating exceeds the ampacity of the conductors, it is a code violation. Instead you need to attack the SOURCE of the heat, and remove that.

jk

Land of 1000 Lakes? I'm shocked, shocked I say!

Everyone else has jumped on this one, and I didn't see anything really wrong.

If you bumped the breaker up from 80A to 100A, did you make sure the wires were rated for it? You could be setting yourself up for a big disaster when the wires heading out to the wellhead burn up in the pipe.

And if you decide to ventilate long term, make screened inlets at the bottom and put hub fitting(s) on top with a 180-degree pipe return bend (two 90's) for the exhaust - rain and dirt falling in is bad. I'd get an engineered ventilation solution to keep UL happy - the whole idea of that steel can is to contain any fires inside the equipment enclosures till they can burn themselves out.

Breakers do wear out, if the switching contacts get pitted from opening under load (and trip-outs count) the resistance goes way up and they get hot, which trips the long-delay thermal section faster.

They are supposed to hold 100% current indefinitely and 125% current for roughly 1 to 2 hours at normal ambient temps (plus or minus quite a bit depending on the trip curve). But when it gets hot in the can the sensitivity goes up and the time goes down.

If these are Challenger C style they're cheap and easy to change - if they're the old Cutler-Hammer CH style with the pin type buss they are more expensive, but available

The start cap accounts for that, since it's going to move the load from straight inductive. It'll even throw off a "True RMS" meter. But check for ground leakage anyway.

I'd say the well pump and motor are getting old - when was the last time they tripped the pump out of the well and checked the bearings and impellers?

Do you have either 240V or 480V 3-phase available? 15-HP continuous duty pump motors should really be running on 3-phase, and the higher voltage gets you half the running current - suddenly you can afford big enough wire to properly compensate for distance.

And when you replace the pump panel, make sure it has an electronic overload on it - if the pump single-phases you want to catch it NOW, not in 30 seconds when the overload heaters in an old-style motor starter finally heat up and trip out.

-->--

Wait a minute. If the motor's rating is 10 A, and you use an 8 A breaker, that guarantees a trip EVERY time. Did you mean the motor's run current should be no more than 80 % of the breaker's rating?

Jon

Client called me Thursday..all in a panic. Seems his OmniTurn CNC lathe blew a fuse when it got hot in the shop. And when he replaced the fuse..it blew again. So we phone diagnosed everything..couldnt find the problem.

Then I mentioned that this is wierd, blowing 15 amp fuses like that with no sign of a short, burned wiring etc....

Long pause..."15 amp???"

"Ah...Ive been putting in 5 amps......"

"let me call you back after I go buy some 15 amp fuses"

Saturday he calls me up, happy as a pig in s*it..been running for two days with no failures

Seems he has been running for at least 2 yrs with a 5 amp fuse in a 15 amp requirement. Which doesnt say very many good things about the fuse manufacture or their ratings....

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the s*it out of you for torturing the cat." Gunner

...

You're right here. This pump is not long for this world. I just found out they don't supply a 15 horse one phase anymore. Don't make the same GMP rated impellor unit either.

I can't go smaller. Sooo, I'm looking at a 20 horse three phase pump. I have your standard one phase 200 residential service. Considering that it runs all day long when its EXTREMLY HOT, and I'm almost certain we see voltage drop problems, what equipment should I use to make my own three phase? Should I hop voltage up with a transformer?

Karl

One further addition would be that if you replace the panel replace it with a one using bolt on style breakers like QOB. For a panel that has continuous heavy loads like that I'd vastly prefer a panel where all the connections can be regularly checked and tightened as with the bolt on styles.

If you replace the whole mess, really take a look at options for a three phase pump fed from a VFD. Another option would be several smaller pumps so that problems with one don't leave you completely dead out of the water.

Pete C.

Can you go multiple pumps? That would enable smaller.

Rotary phase converter.

To what purpose?

The nameplate rating is the full-load max. How much the motor actually draws depends on what machining is being done. I bet it was the combination of high temp and high load that popped the fuses. Few people actually load their machines to absolute max day in and day out.

Joe Gwinn

...

It costs about 15K to drill another hole, so multiple pumps is not a good option.

I just looked, a 30 horse VFD is not that expensive.

Karl

no

I've got a large RPC for my 20 hp lathe. It really bogs the whole place down when starting the lathe with no load. A pump is actually under INCREASED load at startup (no water pressure in lines - pump tries to lift it all at once). I'm very doubtful this would work.

Karl

No reason you can't put multiple pumps down one hole as long as the total flow rate won't exceed the wells capacity. Not sure how big a hole you have, but I bet you can fit three smaller pumps just fine. Perhaps can fit three 5HP three phase pumps? Should stagger the heights a couple feet to avoid cavitation issues.

As far as I know current VFDs are quite reliable and pretty readily available should one fail and you need a quick replacement. You do need to check carefully that a particular unit will accept single phase power input, most smaller units will, but the larger you go the more you run into units that won't.

As has been noted, VFDs provide a lot of nice functions for pumps including soft start. They also will allow you to throttle the pump down a bit if needed.

Pete C.

For a VFD this size, on one phase input, I know I'm on my own. There ain't a techie in this world that will warrant his product for this application. I ran into this on a 10hp. unit for my CHNC lathe.

I'd really like to hear from an experienced electrical power guy what he'd use.

Karl

Yaskawa is the only mfr I'm familiar with that gives single phase input ratings in their printed literature for drives in this size range - up to 30 or 50HP, IIRC. Very nice drives and excellent documentation.

The Magnetek GPD VFDs were made by Yaskawa, but I don't think they're rebadging their drives for other companies anymore.

Yup, I didn't proofread what I wrote. You want to draw a max of 80% continous of the breaker rating.

John

On a pump with a constant load you could use a start run cap setup like you would with a rotary converter but without the extra motor. Since the load is constant you don't need an idler motor but you would have to figure out the amount of run caps to get the proper phase shift at the current draws you are getting. The idler motor only is necessary if your load varies a lot otherwise the caps will work fine. Its the same thing as a single phase motor with start/run caps.

John