Floating earth - generators

[tommy.dale]

Evening gents,

i was wondering if anyone had any links or if someone could explain in leymans terms Any information about floating earths in generators, never had any experience in them and hate not knowing things when they could come in handy one day!! Doesn't have to be any specific just a quick over view which I could possible learn something from.

also I've heard stories about when overseas (afghan army camp) some equipment is run by both USA and our own 230v how is this stepped up or stepped down from the same source? Sorry if im being vague

thanks in advance for any replies

tom

 

[Farmelectrics]

In our place the generator earth is connected to its own earth mat it's separate from the buildings main earth I think something along the lines of if there's an earth fault on the building and the electric trips it won't take the gunny out there for the gunny can run essential services in the building ie comms rooms etc

- - - Updated - - -

Gunny I ment the genny

 

[Knobhead]

A floating earth is only used on small site generators. The centre point of the single phase winding is connected to the chassis. This gives an output that must use two pole protection.

 

[GLENNSPARK]

A floating earth is only used on small site generators. The centre point of the single phase winding is connected to the chassis. This gives an output that must use two pole protection.

up to about 7 KVA i think Tony...

 

[Marvo]

A floating earth is only used on small site generators. The centre point of the single phase winding is connected to the chassis. This gives an output that must use two pole protection.

I think it's worth adding that this type of generator is completely unsuitable for backup power for any kind of installation. These generators are for running small loads such as power tools and the odd temporary appliance such a portable pump or compressor.

 

[tommy.dale]

Thanks guys

 

[Outspoken]

Evening gents,

i was wondering if anyone had any links or if someone could explain in leymans terms Any information about floating earths in generators, never had any experience in them and hate not knowing things when they could come in handy one day!! Doesn't have to be any specific just a quick over view which I could possible learn something from.

also I've heard stories about when overseas (afghan army camp) some equipment is run by both USA and our own 230v how is this stepped up or stepped down from the same source? Sorry if im being vague

thanks in advance for any replies

tom

Tony addressed the floating Earth, but with regards the services at FOB's in Af these are run from separate gen Sets because we use 230V single phase/400V Polyphase 50Hz services and the Silly Planks use 120V single Phase, 240V dual Phase 60Hz services. It is possible to use a 120V Tx with a inverter installed for frequency change, but these are only economic at small powers, once you get above about 5kVA the costs is ridiculous and it's cheaper to have two gen sets.

 

[Thefailsafe2012]

Sorry, was going to post a link but fudged it!

 

[Thefailsafe2012]

Tommy this might come in handy, hope the attachment comes out ok!

 

[Knobhead]

Just to give you a laugh, a now dead friend (old age) had the problem of 50/60Hz.

He altered the governor on the generator to give 55Hz. Time went quick for the British, a little slow for the Americans!

BTW we run at 50Hz?

Have a look at:

http://www.dynamicdemand.co.uk/grid.htm

 

[Darkwood]

Just to give you a laugh, a now dead friend (old age) had the problem of 50/60Hz.

He altered the governor on the generator to give 55Hz. Time went quick for the British, a little slow for the Americans!

BTW we run at 50Hz?

Have a look at:

http://www.dynamicdemand.co.uk/grid.htm

Lets all do a joint power down of our CU's on mass and see if we can get the Gen to trip ...... i suggest during Big Brother an ideal time

 

[Knobhead]

Anyone fancy a cup of tea at 20:36? They'll be relaxing after the 20:30 advert break!

 

[tommy.dale]

Tommy this might come in handy, hope the attachment comes out ok!

Very helpful thanks a lot mate

 

[tommy.dale]

Tony addressed the floating Earth, but with regards the services at FOB's in Af these are run from separate gen Sets because we use 230V single phase/400V Polyphase 50Hz services and the Silly Planks use 120V single Phase, 240V dual Phase 60Hz services. It is possible to use a 120V Tx with a inverter installed for frequency change, but these are only economic at small powers, once you get above about 5kVA the costs is ridiculous and it's cheaper to have two gen sets.

Brilliant that's what I was trying to find, 95% sure I'm got a start on the troop withdrawal contract so need to have some reading material to look up
Many thanks

 

[Engineer54]

Tommy this might come in handy, hope the attachment comes out ok!

What this ECA GN does not tell you, is that these small single phase floating earth gen-sets should not be used on household appliances, fine for small resistive loads like kettles and small heaters and the like but not so good with any form of electronic or electronic controlled appliances. Virtually none of these small gensets will incorporate a stabilized regulated voltage output, they will be totally dependant on load vs speed for voltage output!!

Look at the instructions/manuals of any of these small gensets and you will find somewhere in the literature, exactly what i'm saying, and that the manufacturer will not be held responsible for any loss or damage where such appliances have been connected to the gen-set...