power went out, hooked up gen was working then gen lost one leg of power

Thread Starter

sdowney717

Joined Jul 18, 2012
648
WHY, would it do that and not blow its associated breaker?
This just happened at my house.
Just poorly made?? It was an 8000 watt gen set.
Both legs are breaker protected.
I was using 240 vac at the time, an AC unit when it quit.
I suppose either a wire is bad inside the plug panel on the gen, or it burnt out something expensive.

Its 98*F, and the utility power quit for several hours, but at least after the gen quit, I tried utility power and it is back on.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
other interesting thing. The AC quit running, but the AC contactor was on because it was saying run the compressor.
So the other leg of the house circuits had power but seemed to be at a reduced voltage. I have to think about that, maybe it was running through the motor windings or a generator issue?

When I turned off the AC, the contactor I assume clicks off, and the other leg in the house lost all power.
So power for the other house leg was running through the AC contactor and somehow interconnected.

Now back on utility power everything is normal, AC, stove, drier all working on 240vac. And all 120vac things are also fine.

If I designed a gen, I would make it so a breaker would flip off if overloaded, or if overheated windings. Dont the people who make these things care about the basics?

If the gen has burnt out one side of itself, it would be very pricey to fix, and probably basically then junk to me.
 

SamR

Joined Mar 19, 2019
1,293
I would assume the fault is before the breaker. Have lost one leg before and first clue was strange noise from AC unit as its 120v contact pulled but only one leg of its 240V hot. Second clue was half the lights out in the house. The gen set should have overtemp protection to prevent overload and breaker to protect downstream fault. Sounds like an open in the gen coil.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
Well, it might be the breaker switch. Its been off for awhile, and cooled down. I push the breaker switch on and it feels sticky and wants to turn off. Its a dumb looking rocker breaker, kind of like an appliance switch. Feels really flimsy. We are having a huge heat wave till tuesday and I might look at it in the AM. its super hot outside.

It is a Troy built electric start 13,000 watt surge, 8,000 watt run and its been a good generator. I just priced them and wow have they gone up in price.

Maybe a regular panel distribution breaker would work better, be reliable.
 
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Pretty much what the TS said all makes sense.

Amazon says:

WARNING:
CHOKING HAZARD
-- This toy is a marble. Not for children under 3 yrs.

Which is why I don't like Amazon. Trip curves would help. Specifications would help Drilling diagram will help.
e.g. Remove bar. Drill two large holes and 4 smaller ones. Install. Attach bar.

One comment is that if the thermostat on your AC does not incorporate short-cycle protection, either upgrade the t-stat or build it into the system (search for anti-short cycle timers). If the AC starts under load, the surge is enormous and I've seen breakers and fuseholders destroyed.
Usually the time is between 2-5 minutes. e.g. the AC can't turn on unless its been off for say 3 minutes.
 

SamR

Joined Mar 19, 2019
1,293
On a side note... Troy Built, Yazoo and Gravely used to be American Icons. Don't know who owns the brand Name now but mostly making far from what they used to or out of business.
 

Reloadron

Joined Jan 15, 2015
4,569
How exactly are you doing the transfer from mains (utility Company) to Generator power" Where and how are you tying in the generator and any pictures would help. With the generator offline (no connections to the residence) go ahead and run the generator and start by measuring the 120 VAC outlets and then move to the 240 volts ansd measure that output for 240 VAC

Ron
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
I have a panel interlock made by Square-D, so it uses a panel breaker. You turn off the 200 amp main breaker, lift a metal block plate, and turn on the gen breaker. I measured the output at gen outlet and one leg is dead. No 240vac available, but will find out today if the circuit breaker failed on the gen.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
It is the breaker, one side is open, terminal melted.
And the plastic plug melted. I hate these slip together connections.
Sure they are convenient but this is probably why it failed.

Now I can get a 32 or a 30 amp breaker. Might be nice to have an extra 2 amps?
OEM has this set as 30 amp breaker.
What do you think?
 

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Thread Starter

sdowney717

Joined Jul 18, 2012
648
And I think I want to eliminate the lousy harness plug design, contact area inside those metal connectors is poor.
Use wire nuts? There are only 5 wires. The black wire connector overheated, is discolored and melted into the plastic body of the plug.
I was able to extract all 5 wires from the plug.ends
I may have to lengthen the wires of I do that, but IMO, its a failure point..
 

SamR

Joined Mar 19, 2019
1,293
I would stick with 30 and use a common US brand. Since you also have a 30A in the Panel? you might consider a fuse block with slow blow fuses. If you are using the genset as an installed item I would also eliminate the quick connects and hard wire all.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
I would stick with 30 and use a common US brand. Since you also have a 30A in the Panel? you might consider a fuse block with slow blow fuses. If you are using the genset as an installed item I would also eliminate the quick connects and hard wire all.
I bought the Amazon Blue Sea 30 amp breaker, they make good stuff.
The breaker in the gen was made by Carling, it failed because of a poor push on wire connection causing it to overheat, not a great design. Everything with high current loads ought to be secured with a screw.

I snapped off the goofy pins on the ends of the wires leaving a crimped base. I found some big red wire nuts that can hold the wire ends together. Will be much more secure connection. It needs to be separable, the plugs from the gen end, otherwise much harder to work on.. There is enough slack to put it together.
 

Reloadron

Joined Jan 15, 2015
4,569
An 8 KW 240 volt system is about a 33 amp system so I would just stay with the 30 amp breaker. On the bright side you have the problem nailed. More times than I can remember I have seen melted connectors. It starts slow and just snowballs as things heat up. During heavy rains I can't afford to lose power because I rely on a sump pump. I even have a backup generator to my backup generator. After 10 years of service my 13 KW unit finally failed so I just replaced it with a 16 KW unit which can easily even handle the AC (Air Conditioning).

I would look to replace the connector as best you can and try to avoid spade lug connections as best you can.

Ron
 
Totally agree with Ron. The fast-ons are a very weak link. See https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=82004_FASTON_TERMINALS_-_FULL_CATALOG&DocType=CS&DocLang=EN

The Fast-ons are also not created equal. I'd stick with 30A as well. 240 * 30 is 7200. Breaker should handle the 8000 VA peak.
Changing to a new style breaker makes sense.

MAKE sure the AC comes on later. e.g. make certain that anti-short-cycle is working.

I'm not very fond of the wiring. Particularly the use of Fast-ons. I don't know exactly how I might clean it up.
Looks like a 30 A breaker feeding two 20 A outlets. Your not using those anyway. Separate breakers for the 120 outlets would not hurt.

Home-run wiring would help. e.g. Euro terminals in a NEMA box. Since this doesn't look like it's enclosed, don't forget to have drip-loops.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
its got two 20 amp push on breakers, one for each outlet. I almost never use the 120 vac outlets.
It is enclosed, it has a back cover, I did not take a picture. The entire box has a sheathed bundle of 7 wires coming out, that joins to the wire bundle coming from the generator. IT used that big black plastic plug which failed, joining bundle to bundle. It also failed due to high heat from poor high resistance connectors. It took some effort getting it apart.

I am planning on just joining wire to wire with big red wire nuts.
I am leaving the crimped ends on the wires, so they are more like pins.
can also wrap it with tape.
 

Reloadron

Joined Jan 15, 2015
4,569
That should work. That's what I do sometimes if the wire nuts are in a harsh environment. I tape them just to give a little more protection from the elements.

Ron
 

Lo_volt

Joined Apr 3, 2014
81
I'm not sure the average Fast-on is rated for 30 amps. Definitely a weak link.

While you're into it, look to see if it has brushes. A coworker of mine related a story about a Troy-bilt genset he had that failed because the springs to push the brushes were not properly installed. They worked fine initially, but with a little bit of wear, they started to lose contact. As I said, if you've got the unit open already, you might as well check them.

I believe MTD bought Troy-bilt about 20 years ago. The quality has not been the same.
 
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