Generator advice required

[gensetsteve]

The momentary startup load on electric motors is far more than their rated running kw.

 

Also for example, a fluorescent light may run at 30w but may need 150w draw on startup, so if you have a bank of 20 lights it's a fair old startup current

 

If I was running a 2kw motor I would buy a 4kw genny

 

Also need to allow a bit more if you have a long cable run

 

 

Hi Dean

The start up current on fluorescent or capacitive lighting is hard on generators because of the power factor. I went to a factory years ago that had a 5kw honda with 50 lights loaded within max output. But when they switched the lights on it blew the diodes in the generator. normal tungsten lamps no problem same as putting a heater on.

 

To start a 2kw motor without long sterm damage to the windings you will need 7-8 kw or 10 kva.

 

Long cable run will cause a volt drop the only way round this is bigger cable as long as set is big enough getting a bigger one wont help.

[gensetsteve]

Hi Bob looked into this two year ago when i was going to go down same root.Wasnt sure about whether would be suitable or not as kindlet pro requires alot of juice to get it going dont quote me on this but something about a delta???start i think.But thanks for your input.

 

kindlet will probably be direct on line ie no soft start or star delta starting. Not sure if you can soft start a hydraulic pump with pressure relief valve. Maybe talk to richard at fuelwood.

[Dean Lofthouse]

 

To start a 2kw motor without long sterm damage to the windings you will need 7-8 kw or 10 kva.

 

Blummin ek ! I never would have thought that

[gensetsteve]

I would be interested to hear peoples views, as I am in the same boat as well, currently using a single phase pto generator. I will in the near future be planning to purchase a 3 phase kindling machine as well as running other 3 phase motors. I am considering mounting a 3 litre transit engine onto 2 RSJ's and run these through a David Brown back end/gearbox. I would like to try and run the engine on LPG as I have heard that Diesel engines gum up due to not being worked hard. I would appreciate any comments or criticisms that people have . I cannot justify 5K at the moment on a self contained generator.

 

If it was me I would have a mooch about the plant auctions and buy an open 50 kva diesel set 1500 rpm for about £1500 . I see lots of home made efforts you dont need a gearbox all you will do is introduce friction and headaches. Most of my part exchange sets of this value go straight to the auction so there is no confusion as to who is paying for the repairs when they overload it 24/7 for 3 months If you size the set correctly and try and run it at least half load you should not have problems with glazing or slobbering. If you find you do add 3 short wave heaters for the workshop into the mix should help out. A one hour run at full load every few weeks normally sorts them out. For £500 I can bring my £15,000 load bank and do it for u

[openspaceman]

 

If I was running a 2kw motor I would buy a 4kw genny

 

 

My 4kVA genset actually won't start my 2kW compressor unless I start from an empty air tank.

[Dean Lofthouse]

My 4kVA genset actually won't start my 2kW compressor unless I start from an empty air tank.

 

It would start if it had blown off, you know when it reaches pressure and releases the air in the pump circuit, unless it is an old design that doesn't ??

[openspaceman]

It would start if it had blown off, you know when it reaches pressure and releases the air in the pump circuit, unless it is an old design that doesn't ??

 

It doesn't blow off, when it reaches pressure it cuts the power to the 2kW motor, as pressure drops the switch cuts the motor in and stalls the genset. I still think of it as new :-(

[Dean Lofthouse]

Lol, must be old, mines an ancient broom wade and that blows off.

[gensetsteve]

I am ancient an even I blow off. strictly speaking according to the textbook you need 6 times running current to start a motor. But in practice you can get away with 3 times so 10kw will start with 30kw. Just need to be careful the volt drop does not damage equipment elsewhere or damage itself. Also alot depends on how much load is on the motor when it starts and whether it can be stalled whilst running.

[Dean Lofthouse]

Thanks Steve, I have learnt something there