How not to change voltage regulator in genset

Topic: How not to change voltage regulator in genset (Read 1625 times) previous topic - next topic

How not to change voltage regulator in genset

November 19, 2017, 09:57:34 am

The voltage regulator was bad in my 10kw Powertech and I ordered a new one from Powertech. It came on a Friday afternoon and Powertech was closed until Monday. It came with 2 schematics, one for a 120v generator and one for a 120/240 generator. Using the one for a 120v as my generator was labeled 120v I figured I could change it out. I took pictures and labeled wires. The regulator in the generator had the same part number as the new one so matching up the new regulator to the old connection points seemed simple enough. That was the big mistake. When I started the generator it let the smoke out. On Monday I called Jeff at Powertech and explained what had happened. He asked if I had followed the schematic and removed any wires not on it. When I told him I wired it up the same as the old one he informed me I had burned up my generator. You have to cut one wire that goes to the regulator number 3 wire. The pictures show the story. After ordering a new generator and receiving it on a Friday afternoon again. I proceeded to install the new generator. It is labeled 120/240v and looking at the schematic labeled 120/240v and seeing all the wires reversed from my old generator decided to wait an talk to Jeff on Monday. It was a good decision as he told me to follow the schematic for the 120v generator and not start it up until I was at the generator and had him on the phone. Verifying I had each wire correct he then gave me the go ahead to finish the installation. I don't know why the schematic doesn't mention cutting the wire that will destroy the generator if you don't. It was a expensive learning experience and just waiting until Monday and talking to Jeff before starting the generator would have saved about 3 CB's
Sorry for the long post but maybe it will save someone else from making the same mistake.

Re: How not to change voltage regulator in genset

Reply #1 – November 19, 2017, 10:39:11 am

OUCH! That is what is called learning the REALLY hard way! Sorry to hear about this, but many thanks for posting the story. You have probably saved some future owners from making the same mistake. I hope this report is immediately incorporated into the Forum Knowledge Base Wiki.

So (in your photos) where (or what) is the voltage regulator? Is it the white gizmo screwed to the back of the metal cabinet?

Re: How not to change voltage regulator in genset

Reply #2 – November 19, 2017, 10:45:32 am

That is the voltage regulator and the wires are labeled the same as the new regulator. Below are the schematics sent with the regulator. The number 3 terminal has 2 wires hooked to it from the factory, the one that goes to ground has to be removed.

Re: How not to change voltage regulator in genset

Reply #3 – November 19, 2017, 03:05:45 pm

What were your symptoms that caused you to replace the voltage regulator?

Re: How not to change voltage regulator in genset

Reply #4 – November 19, 2017, 05:14:59 pm

Generator would stop making voltage. The trouble shooting advice from Jeff at Powertech was to check voltage at the main breaker. When and if that happened and if it had more than 4 volts it was the voltage regulator. When it quit on me on vacation it read 9 volts. It was very sporadic, would go weeks no problem then no voltage. Turn the generator off and wait anywhere from 5 min. to 2 hours and it would start working again.

Re: How not to change voltage regulator in genset

Reply #5 – November 19, 2017, 10:31:50 pm

Thanks craneman, good to keep in mind

Re: How not to change voltage regulator in genset

Reply #6 – November 19, 2017, 11:14:27 pm

Not to thread jack but I just got into mine today. Saw it reading 150 volts last time I had it running. Thankfully all my computer/tv stuff is on UPS and it has high voltage cutout. Anyway, got in there and found two screws loose and when I started it again all seems well. But, I have the same terminal strip pictured but for the life of me I don't see any labels on the wires, on the terminal block, anywhere. If I had to replace this (identical) regulator, how do you go about placing and verifying the wires on the terminal blocks and elsewhere?

Re: How not to change voltage regulator in genset

Reply #7 – November 20, 2017, 10:00:38 am

When You install a new regulator you do not use the terminal strips according to Jeff. Farther down the wires are labeled. The regulator has the 4 connections labeled. They are F+, F-, 3, and 4 3 was the one that got me as originally it went to the terminal and there were 2 wires there. Number 4 goes to the 4 amp circuit breaker. look in the first picture and you will see the white bands with the wire id's on them

Re: How not to change voltage regulator in genset

Reply #8 – November 20, 2017, 11:20:15 am

I hope Powertech gave you a little break on the new generator! Seems they should bare some of the responsibility. Something that damaging should be spelled out in large red letters on the diagram! It's easy to Monday morning quarterback but their tech was working with you before you installed. He should have given some warning about the installation of the regulator.

Damn I hate it when the smoke comes out and the CBs fly away.

Glad you at least have a working generator now.

see ya
ken

Re: How not to change voltage regulator in genset

Reply #9 – November 20, 2017, 04:54:26 pm

No break. I believe because if I had waited until Monday before installing the regulator this would not have happened. Jeff is very good at helping with generator problems and he would have stopped me from using the terminals. The new regulators have spade connectors and the generator wires hook directly to the regulator. They assumed that I would realize that the extra wire on number 3 terminal of the old regulator would not be in the system.
Yes I have a NEW working generator now.

Re: How not to change voltage regulator in genset

Reply #10 – November 20, 2017, 06:19:14 pm

Craneman,
Thanks for sharing the info. I'm sure many of us have made some costly mistakes. I know I have. Instead of getting mad at the situation I just chalk it up to the cost of learning. Sometimes our confidence and accomplishments is what gets us into trouble. I agree, somewhere in the documentation it should of said to cut the wire.
Thanks, John M.

Re: How not to change voltage regulator in genset

Reply #11 – November 20, 2017, 06:31:04 pm

I have no animosity towards Powertech on this issue. Imagine what would have happened if I hadn't waited until Monday and talked to Jeff, after installing the new generator, and wired it up according to the 120/240v schematic. I would have fried all of the components in the coach as I don't have the Progressive installed yet.

Re: How not to change voltage regulator in genset

Reply #12 – November 20, 2017, 10:40:15 pm

Did you get a core charge refund for the smoked part?

Re: How not to change voltage regulator in genset

Reply #13 – November 21, 2017, 12:05:43 am

Quote from: Old phart phred – November 20, 2017, 10:40:15 pm

Did you get a core charge refund for the smoked part?

There is no core charge on the new one. Toast is toast. It is in my scrap metal pile. They don's sell rebuilt ones. I priced a used one at one of the RV scrap yards and they only sell the complete unit not the pancake generator part. It was more money than the new one. The 3 CB's included a new $400.00 regulator and shipping from Florida to Los Angeles. Jeff said that the new regulator that fried the generator could have issues, so no chances were taken.

Re: How not to change voltage regulator in genset

Reply #14 – November 21, 2017, 04:39:53 am

MOT changed out mine and friend the end. This is an issue with these new regulators. Mot stepped up and paid for the new end to be installed as they did not send out wiring instructions. When I had a Powertech place change the end for me we called and verified with Jeff but this is the. 4th one I have either seen or heard about doing this.

Re: How not to change voltage regulator in genset

Reply #15 – November 21, 2017, 12:44:56 pm

Add me to the list. Several years ago, at an FMCA rally, my voltage regulator started putting out 150 volts. Power Tech was at the rally and came over and changed out the regulator. After the Power Tech technician finished wiring the new regulator we started the generator and smoked it!!!

Re: How not to change voltage regulator in genset

Reply #16 – November 21, 2017, 07:00:28 pm

I am sure this is a one time learning experience for everybody, too bad it is so costly. It defies logic that a new regulator wired the same as the old one can do so much damage, especially since they have the same part number. But I won't make the same mistake twice.

Re: How not to change voltage regulator in genset

Reply #17 – November 21, 2017, 08:59:10 pm

The PowerTech 'Problem' about toasting the generator part, often called pumpkin when installing a PowerTech supplied voltage regular is a BIG problem not being addressed by PowerTech.

There have been several, maybe many who have been burnt by this unacceptable issue. Others have had their simple voltage regulator problem cost them several thousands of dollars because, in my opinion, PowerTech does not choose to supply a different voltage regulator part number for the significantly different generators.

Generators have model numbers, and because of the terrible damage that can so EASILY happen by technical, experienced and coach-owner installers alike, each generator type should have its own voltage regulator PowerTech part number. We like PowerTech a lot, and appreciate their high-level of cooperative technical support, and wish they would see the light and try to mitigate the pain their choice has caused.

Check out this post from two years ago and see this is a longtime ongoing problem.

VERY IMPORTANT - 10KW Isuzu generator voltage regulator DESTRUCTIVE PROBLEM

Voltage regulator failures are a common situation with voltages jumping up to 160 or so and then back down to normal. So changing them should be very straight forward, and most buy replacements from PowerTech. I have heard that PowerTech has offered some concessions to owners who have burnt up their gen by reducing the cost of the expensive replacement generator end.

Re: How not to change voltage regulator in genset

Reply #18 – November 24, 2017, 10:04:21 pm

So if I am to understand this right, in the black wiring coming from the generator head and exciter, there are multiple wires that terminate to the #3 labeled wire and one of those wires needs to be cut. Are you supposed to just use a meter to check which one goes to ground and chop and tape it off?

It sounds like this is on the generator side wiring and not within the regulator. I suppose the reason I am asking is that I can't help but notice the same regulator is less than half the price of powertech from other sources. If I were to carry a spare, it'd be nice to pay less. But fully understanding how it all works would be key to not smoking it.

Re: How not to change voltage regulator in genset

Reply #19 – November 24, 2017, 10:30:31 pm

Quote from: Mark D – November 24, 2017, 10:04:21 pm

So if I am to understand this right, in the black wiring coming from the generator head and exciter, there are multiple wires that terminate to the #3 labeled wire and one of those wires needs to be cut. Are you supposed to just use a meter to check which one goes to ground and chop and tape it off?

It sounds like this is on the generator side wiring and not within the regulator. I suppose the reason I am asking is that I can't help but notice the same regulator is less than half the price of powertech from other sources. If I were to carry a spare, it'd be nice to pay less. But fully understanding how it all works would be key to not smoking it.

On the original regulator there are 4 wires they are labeled at the regulator. 3 of them go to a terminal strip F+. F- and number three. The 4th wire labeled number 4 goes to the 4 amp round circuit breaker. It is the number three wire that goes to the terminal strip where there are 2 wires at that terminal. The wire that goes to the ground lug at the back of the box is what kills the generator. According to Jeff if you don't use the terminal strip and hook just the wires on the schematic to the matching wires on the new regulator you will be ok. The problem has been matching up the new regulator the same as the old leaves the ground in the system. As for the regulators online for under a $100.00 compared to $350.00 from Powertech I am not going to be the guinea pig finding out if it will work. The price of the generator is too high.

Re: How not to change voltage regulator in genset

Reply #20 – November 25, 2017, 12:46:27 am

This is an excellent description and now I fully understand the situation. I suppose I'll soul search as to whether or not I'm willing to take the risk

Affiliate Notice