testing voltage on 110v systems

[tbs1983]

Hi guys, not really done any 110v work and not something we ever covered in detail in college.

A workshop with fixed 110v outlets was having trouble with a 110v appliance,
Upon voltage testing the outlet I got the following readings:

L-N - 57v
L-E - 0v
N-E - 57v

Are these readings what I should get? Im unsure as Ive always worked on the 230/400v principle that L-N and L-E should produce voltages and N-E be 0v so its throwing me a bit.

I understand the basic principle that 110v works on a centre tapped earth therefore combines the two 55v to create the 110v.

Any advice would be greatly appreciated.

p.s. other 110v appliances work fine from the outlet so were assuming its the appliance at fault but I'm curious as to the above.

 

[telectrix]

.think you;ve measured wrong. L-L = 110V. each L -E =55V. there's no N on a 55-0-55 110V

 

[ian.settle1]

.think you;ve measured wrong. L-L = 110V. each L -E =55V. there's no N on a 55-0-55 110V

Don't forget it could also be L-L = 110v and L-E = 63.5v if the supply from a 3 phase transformer

 

[telectrix]

smart-arse. :-------:

 

[elliot123]

Bit of a silly question but recently done some temp 110 lights for a site and I was always told a bulb won't strike with out a neutral but in a 110v system there is no neutral?

They Definitely don't cover enough 110v systems in college barely Learnt about them expect their used on building sites and it's centre taped to earth

 

[telectrix]

a bulb requres a voltage across it. it can't differentiate between L-N, L-E or L-L. as long as thers a potential of sufficient magnitude ( e.g. 110V in this case)

 

[elliot123]

Ahh I see thanks, just one of those silly things where I got confused with the concept due to being told bulb won't strike without a neutral

 

[telectrix]

if the light is wired conventionally, e.g. in a house, across L -N, then you're right. if the N is lost, then the lamp won't work. however ( and this has given guys belts) because there's no current flow, the volt drop across the lamp iz 0V, so you will get 240V on the N side of the lamp.

 

[tbs1983]

Thanks Tel, can't recall ever covering 110v in college in any detail and its taken 10 years to come across it in the real world.

 

[ian.settle1]

Bit of a silly question but recently done some temp 110 lights for a site and I was always told a bulb won't strike with out a neutral but in a 110v system there is no neutral?

They Definitely don't cover enough 110v systems in college barely Learnt about them expect their used on building sites and it's centre taped to earth

Definatly be buggered on ships then as there is no neutral on 99% of them

 

[telectrix]

isn't buggery on ships standard practice?

 

[Pete999]

Centre tapped safety transformers most 110v supplies rely on this for safety reasons, 57v-0v-57v as said before lamps require a voltage applied across the terminals. Got a feeling the Yanks derive their 220v this way although I couldn't be sure, 110v-0v-110v = 220v

 

[Knobhead]

Septic's use 115/115/230V

 

[shanky887614]

Definatly be buggered on ships then as there is no neutral on 99% of them

Or cars, doesnt everything end in an earth?

I know on old ships they used to use the hull as the return path or so ive heard

 

[Pete999]

Septic's use 115/115/230V

You sure thought Septics was 220v as Mike Holmes keeps telling us, I know he's Canadian but it's all the same over there isn't it?

 

[SparkyJoe]

Or cars, doesnt everything end in an earth?

I know on old ships they used to use the hull as the return path or so ive heard

The negative of the battery went onto the frame so you only needed positive cabling (At least on the old cars ive played with, dont know so much about modern vechs)

 

[telectrix]

older cars were + earth. remember a couple .

 

[ian.settle1]

isn't buggery on ships standard practice?

Only for the Pursers Department

 

[PEG]

older cars were + earth. remember a couple .

Lots of old plant too,i've converted plenty years back,dynamos,reg. boxes,reversed ammeter etc, thinking behind it was corrosion related,apparently. Was actually driving an old Manitou stacker yesterday that i did nearly thirty summers back.....starting to sympathise with that bloke in "highlander"...