Author Topic: LD1 lack of electric power  (Read 220 times)

Electric Chicken

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LD1 lack of electric power
« on: March 30, 2019, 03:03:45 PM »
HELP, Please!
I have an LD 1 with generator attached.
Engine number = 718LD16
Generator number = 12130/232
It is rated to output 1.5 KVA, 230volts, 50 cycles, at 1500rpm.
Was running and powering things fine. Whilst running a small chop saw which it has done countless times before, the saw jammed, the lights went out.
Now it is only putting out enough power to light the indicator light in the battery charger.
I have taken a look in the control box and all seemed fine. As we have had previous problems with the power lead, I have replaced that ... no change.
Sods law - the multimeter got dropped so can't give any readings until I replace that.
Any ideas as to what part has been upset, where to start with fault finding, how to get it back to chucking out decent amounts of power?

Electric Chicken

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Re: LD1 lack of electric power
« Reply #1 on: March 30, 2019, 10:09:24 PM »
OK, from further research, I think that I might have lost residual magnetism. Apparently, you can flash the generator to excite the magnetism.
Does this sound like a possibility?
If so, what do I connect the battery to?
Any help, gratefully appreciated

ajaffa1

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Re: LD1 lack of electric power
« Reply #2 on: March 30, 2019, 10:40:00 PM »
Good day Electric Chicken, welcome to the Forum, sorry to read you are having generator problems.

The situation you describe, in which you overloaded the generator when the saw jammed, suggests to me that something has blown. Does the generator have a fuse built into it or an overload reset button?

You are very unlikely to have lost residual magnetism unless you shut the generator down with the load still connected.

Do you own an old fashioned 240 volt electric drill? If you do, start your generator, plug in the drill, pull the trigger and then manually turn the chuck in the direction it would normally go. The residual magnetism in the drill winding should be sufficient to get things going, the voltage will build slowly back up to normal.

Good luck, let us know how you get on.

Bob

Electric Chicken

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Re: LD1 lack of electric power
« Reply #3 on: March 31, 2019, 12:51:11 PM »
Thanks for the reply.
I thought the same thing and was worried about the voltage regulator. Especially as when I looked in the control box, some if the paint covering has flaked off it which leads me to think that it got hot.
On a more positive note. I had an old petrol Genny that had packed up giving out a voltage after being left for a winter. Tried the electric drill trick on that .... It didn't work but when I swapped the voltage regulator, hey presto ... Power!
I will try the drill trick on the old Lister and see what happens. I have tried a replacement fuse (it has a 13 amp fitted). The only other components that are in the control box are the starter solenoid, a "high/low" switch???, 2 huge coils and what looks like a big diode ( ie it looks like the old zenner diodes that I had on the triumph).
I am hoping that if it is the diode, then I can get a replacement. Not sure where to look for one though.

ajaffa1

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Re: LD1 lack of electric power
« Reply #4 on: March 31, 2019, 01:17:50 PM »
Hi Electric Chicken, could you please post a few photos of what you have got, that will help us talk you through trying to fix it. Posting pics is easy just click on the "Attachments and other option" at the bottom of your text box.

Sounds from your description, very much like a standard Lister top box with a couple of large rheostats and a high/low switch to control battery charging. The Diode is to prevent the battery discharging through the field winding when stationary. I suspect that the wiring is something similar to the attached.

Bob

Electric Chicken

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Re: LD1 lack of electric power
« Reply #5 on: March 31, 2019, 02:11:02 PM »
Thanks for the diagram, Bob. Most useful.
I have tried the drill trick but to no avail.
I now have a new multimeter, so tested the output from the generator and it is only pushing 20 volts down the line. I will try to attach some photos of the control box but it does sound like the standard box that you described.

ajaffa1

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Re: LD1 lack of electric power
« Reply #6 on: March 31, 2019, 10:44:02 PM »
Hi Electric Chicken, if you take the two plastic covers off the side of the generator head you should find two more wire rheostats and a bride rectifier. Test these with your meter to confirm continuity, also check the condition of the slip ring brushes.

Old selenium rectifiers and bridge rectifiers can easily be replaced with modern silicon components for next to nothing. Replacement brushes will be a lot more expensive and hard to come by, the size and type will be written on the generator head identification plate.

A while back I posted a lot of photos and information about these heads, in response to questions from Alexdick, you might want to check them out.

Bob

ajaffa1

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Re: LD1 lack of electric power
« Reply #7 on: March 31, 2019, 10:49:47 PM »
Further to my last, the information is the Generator section under SDA/SDT. It shows how to replace bridge rectifiers and etc.

Bob

Electric Chicken

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Re: LD1 lack of electric power
« Reply #8 on: April 01, 2019, 08:33:28 AM »
Thanks for your help, Bob. I will take a look and let you know how I get on.