Generator

[Gary A]

I recently bought a second hand 500 watt Robin generator. The guy I bought it from wasn't very truthful but that is beside the point. I finally got it running and the governor seems to keep it at a steady speed. The problem is that the voltage jumps all over. My volt meter reads from 190 volts up to 250 volts without the engine changing speed. It carries a load but I am afraid to use it for anything electronic. When I check the house voltage, the reading stays very steady at 242 volts so I'm sure my voltage meter is working OK. Anyone have any ideas?

[Crossy]

I wonder if it is unhappy running off-load.

If you run a 60W lamp does the output still fly all over the place?

If you're (rightly) nervous about your electronics get one of those cheapie ferro-resonant AVRs, the transformer should also clear up any spikes and other orrible stuff

Edited May 29, 2008 by Crossy

[Gary A]

I wonder if it is unhappy running off-load.

If you run a 60W lamp does the output still fly all over the place?

If you're (rightly) nervous about your electronics get one of those cheapie ferro-resonant AVRs, the transformer should also clear up any spikes and other orrible stuff

The generator has two outlets. I plugged an electric motor into one and the volt meter into the other. The voltage is still constantly going up and down. It doesn't just drift, it just varies like crazy.

[Crossy]

It may not like a motor load, try it with a lamp.

If the result is the same, could be brushes (unless it's brushless of course), or an iffy connection in the regulator circuit, have a poke around for loose wires.

If it has any electronics on a circuit board look for 'dry' joints, you may need your magnifier and a good light.

If it is brushless, there may be some diodes on the rotor (they go round with the generator) check for iffy connections there too.

Edited May 29, 2008 by Crossy

[Gary A]

It looks to be sealed pretty well. No obvious inspection ports or open areas. I think I'll take it to a small electrical shop and see if that guy can check it out. I took a Makita hand drill to him. He checked it out and said he could fix it but it would be better to buy a new one so he appears trustworthy.

[Crossy]

It looks to be sealed pretty well. No obvious inspection ports or open areas. I think I'll take it to a small electrical shop and see if that guy can check it out. I took a Makita hand drill to him. He checked it out and said he could fix it but it would be better to buy a new one so he appears trustworthy.

Yeah, I'm tempted to agree (although personally I'd have it in bits all over the kitchen table by now).

These things tend to have lots of "ping-fcukits" inside, a technical term for those little springs that go 'ping' whereupon you say '<deleted> it'

Do try it with a lamp before going to the man though

Edited May 29, 2008 by Crossy

[Gary A]

It looks to be sealed pretty well. No obvious inspection ports or open areas. I think I'll take it to a small electrical shop and see if that guy can check it out. I took a Makita hand drill to him. He checked it out and said he could fix it but it would be better to buy a new one so he appears trustworthy.

Yeah, I'm tempted to agree (although personally I'd have it in bits all over the kitchen table by now).

These things tend to have lots of "ping-fcukits" inside, a technical term for those little springs that go 'ping' whereupon you say '<deleted> it'

Do try it with a lamp before going to the man though

I did plug a bug light into it and still had the problem. Believe it or not, I don't have an incandescent light to plug into it. I'll have to go buy a bulb and socket to test it. I need a drop light anyways.

[Crossy]

Since you had trouble getting it going, do you have any means of checking the RPM or frequency (3000RPM / 50Hz). If it's well off the regulator my be having trouble sensing and maintaining the output.

Just checked, I have only two incandescent lamps, obviously we are both energy conservers

Edited May 29, 2008 by Crossy

[Gary A]

Since you had trouble getting it going, do you have any means of checking the RPM or frequency (3000RPM / 50Hz). If it's well off the regulator my be having trouble sensing and maintaining the output.

Just checked, I have only two incandescent lamps, obviously we are both energy conservers

Regulator? I can adjust the governor and the voltage goes up and down. If I slow it down, I can get 100 volts and speed it up to get over 300 volts.

[Crossy]

Regulator? I can adjust the governor and the voltage goes up and down. If I slow it down, I can get 100 volts and speed it up to get over 300 volts.

OK, there are two variables:-

1. The governor that controls the engine speed and hence the output frequency, for 50Hz 3000 RPM would probably be the correct speed for such a small genset a bigger set may run at 1500RPM.
   
2. The regulator that controls the generator output voltage by adjusting the magnetic field strength.
   

Since adjusting the speed makes a vast difference to the output voltage I suspect that the regulator is busted. However without seeing the beastie and having a diagram it's really not possible to pass judgement. Could be time to visit the man

You may find that setting the speed correctly will make everything happy (or it may not).

Edited May 30, 2008 by Crossy

[Gary A]

It's probably quite obvious that I know nothing about generators. I suspect that you are right and that the regulator is not working. The days of mechanical contacts are long gone.

[Khonwan]

It may not have a regulator (they add a significant cost to the basic generator price AFAIK). My Honda had one, my current Honmar does not.

Rgds

Khonwan

[Crossy]

It may not have a regulator (they add a significant cost to the basic generator price AFAIK). My Honda had one, my current Honmar does not.

Actually the Honmar (or for that matter Garys Robin) may have a capacitor regulator, a dead simple system that has a single capacitor (about 22uF @ 250VAC) driving the field windings.

I discovered these things whilst Googling for a hint as to what Gary's problem could be. Unfortunately technical information on exactly how they actually work seems limited

Edited May 30, 2008 by Crossy

[Gary A]

It may not have a regulator (they add a significant cost to the basic generator price AFAIK). My Honda had one, my current Honmar does not.

Actually the Honmar (or for that matter Garys Robin) may have a capacitor regulator, a dead simple system that has a single capacitor (about 22uF @ 250VAC) driving the field windings.

I discovered these things whilst Googling for a hint as to what Gary's problem could be. Unfortunately technical information on exactly how they actually work seems limited

I'm quite disappointed that there seems to be VERY little information available for this unit. It is a R600 Robin generator Fuji Heavy Industries.

[Gary A]

I found an R650. Hopefully they are similar. The picture looks the same.

Generator - Brushless,self exciting,2 poles,single phase

Voltage Regulator - Condensor Type

[Crossy]

I found an R650. Hopefully they are similar. The picture looks the same.

Generator - Brushless,self exciting,2 poles,single phase

Voltage Regulator - Condensor Type

Aha, a condenser (capacitor) regulator.

A 2 pole generator needs to run at 3000RPM to give 50Hz, it's important this is close for the regulator to work correctly. Does your multimeter measure frequency? If not adjust the speed for 220V as a starting point.

Then we're back with looking for loose wires (since the output jumps around rather than drifting I'll put money on an iffy connection).

The capacitor regulator is very simple, locate the capacitor and replace it

[Gary A]

I found an R650. Hopefully they are similar. The picture looks the same.

Generator - Brushless,self exciting,2 poles,single phase

Voltage Regulator - Condensor Type

Aha, a condenser (capacitor) regulator.

A 2 pole generator needs to run at 3000RPM to give 50Hz, it's important this is close for the regulator to work correctly. Does your multimeter measure frequency? If not adjust the speed for 220V as a starting point.

Then we're back with looking for loose wires (since the output jumps around rather than drifting I'll put money on an iffy connection).

The capacitor regulator is very simple, locate the capacitor and replace it

The old Pattaya Frenchman, Phillipe, saw me coming. I took the instrument section apart and found one indicator bulb and socket totally gone and the other looks like the bulb is shot (black). It does have a Hz meter. It appears to have three lights with numbers 40,50 and 60 on the meter. None of the three lights work. It looks like no wires are missing. It is obvious that it has been apart many times before. Anyways, I took connectors apart and plugged them back in. None corroded and none that appeared to be loose.

There are two black boxes on the generator frame. One about 1.5 inches by 3.0 inches and the other much smaller. I assume the bigger one would be the capacitor?

I started it back up and have the same condition. It also has a 12 volt circuit that strangely reads 17 to 21 volts when the AC reads from 160 to 210 volts. At as close to 240 volts as I can get, the engine is running pretty slow. I speeded it up to where it sounded about right and I was getting jumps up to 370 volts and DC voltage up to 40. Both black boxes look original.

I'm done playing with it. I'll take it to the electric shop and if he can't fix it, I'll be using it for fans and lights. It's probably something minor, I hope. I paid 4,500 baht for it thinking it was in good running order. The gasoline was old and smelled bad so I assumed that is why it wouldn't keep running. SURPRISE!