Thread: generators

While the cheapies may work for some people, I found the voltage all over the shop. First unit didn't even strike a fluro tube as the voltage was too low (170V). Took that one back and got it replaced. Replacement one did the same. Managed to tweak the voltage back up to 240V but then found as the load changed the voltage would go for another wander. Gave up when a plastic lampholder was smoking and the output voltage up around 380V.

Ended up getting a little honda. Nice and stable, starts first time and quiet. Can run most of the essentials at home in a blackout.

Originally Posted by wander

Seems i was lucky both engels still run okay,mate plugged in a voltage gauge last night and gen was putting out 330 volts not 240.This would explain battery charger going dead and engels shutting down.Thanks for all the replies now looking at a Honda or similar.Solar panel is also on the table for consideration.

Bruce.

Early days of these things flooding the market, we put one up on the bench for a bit of checking over ... plugged a pedestal fan into it and noticed that it was running about 2x speed .... the meter said 385v and 117Hz .... voltage control on alot of these cheapies is the throttle screw ... as the a/f loads up, the things slow down, causing the voltage & frequency to go out of spec', then people wind the throttle up to get the performnce back ... then down the track they clean the a/f and the thing runs overspeed/overvoltage/over frequency

Originally Posted by Fluids

Early days of these things flooding the market, we put one up on the bench for a bit of checking over ... plugged a pedestal fan into it and noticed that it was running about 2x speed .... the meter said 385v and 117Hz .... voltage control on alot of these cheapies is the throttle screw ... as the a/f loads up, the things slow down, causing the voltage & frequency to go out of spec', then people wind the throttle up to get the performnce back ... then down the track they clean the a/f and the thing runs overspeed/overvoltage/over frequency

The $99 Chinese two strokes don't have a controllable throttle. Speed is varied automatically with increased load. Mine barely gets above idle speed with lights only and speeds up to half speed with the fridge on as well. The only occasion it has got up to full speed was whilst using a 240 volt heat gun on the middle setting. If you try to put excess load on it, it just stays in idle mode and refuses to run the offending device.

Ah, that must be a chinese inverter type generator .... a standard type non-inverter generator runs at a fixed 3000rpm to deliver 50Hz power.

Cheapie $99 chinese units are NOT inverters and run at a fixed speed .... speed is controlled by throttle adjustment, then the govenor applies additional throttle to maintain engine speed as load increases.

Only inverter generators run with infinitley varying engine speeds.

Originally Posted by Fluids

Ah, that must be a chinese inverter type generator .... a standard type non-inverter generator runs at a fixed 3000rpm to deliver 50Hz power.

Cheapie $99 chinese units are NOT inverters and run at a fixed speed .... speed is controlled by throttle adjustment, then the govenor applies additional throttle to maintain engine speed as load increases.

Only inverter generators run with infinitley varying engine speeds.

Electrics are not my trade muster, but I can assure you my generator is the usual Chinese two stroke. It cost me $99 and looks identical to all the others that appear to have come from the same factory just with different brand decals. Not one of the ones I have seen have a manually adjustable throttle. The only fuel system control is the cold start lever.

OK. I see. That's right. Generators don't have throttle controls, but they do have an adjustable engine speed screw (the chinese cheapies) which is in essence, a throttle control, or a govenor adjusting screw, to limit revs. It gets set to run the gennie at 3000rpm. It's not a user adjustable setting.

When you load the gennie up, the load causes the engine revs to start to drop, so the govenor opens the throttle, and gives it more gas to allow it to pull that load ... but it's still doing 3000rpm. More throttle, more noise, not more speed.

Cheers

Originally Posted by lewy

so if there is no voltage regulator fitted to these cheap generators is it possible to use something inline to control the voltage.I realise that this may increase the cost up to the price of a honda etc

Late reply I know, but... not as easy as you might think. The way any decent genset works, is that the field of the machine is varied depending on load giving a stonger or weaker magnetic field on the rotor - this gives a stable output voltage of whatever - usually 240 volts. With the cheap sets, there is no easy way to do this, as these machines don't generally have field configurations in the same way as the better stuff does, and some of them have fixed magnets, so no direct regulation is possible. As the voltage of these drops quite low under high load, putting a filter or something in after the alternator would accomplish nothing.

I am looking into this a bit at the moment, as I have had quite a few cheap gensets come through my garage that have had various problems, and while most of them are not worth repairing, there have been a couple I have coaxed back to life, and I have been thinking about a better regulation setup myself for some of these.

Cheers - Gav

No doubt this will spark some interest

In the market for a genset. Given my penchant for bigger is better ... I was trying to rationalise the premium on Honda/Yamaha sets around the 2kva size with a 5KVa pure sine wave inverter remote start diesel genset for $1900...

Pinnacle Wholesalers - Diesel Pure Sine Wave Inverter Generator - GENERATORS

Only problem is that it's damned heavy at almost 100kg...but that aside has anyone had experience with these?

The same outfit has electric winches at a seemingly reasonable price:
4wd Off Road Gear - Pinnacle Wholesalers
same question...