3KV 110V transfomer output
- Thread starter Hager
- Start date
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How do you intend joining the outlets?
Which?
Very wise - 5Kv will make a huge mess of a 110v motor, and could well kill or seriously injure you.
N
Newboy
Hopefully there's an 'A' missing or else that's one hell of a transformer!
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Apologies i'm missing the A.
I don't want to join the outlets just want to make sure that i'm not over loading the transformer.
I realise that its 3A over the current rating for the Ceeforms but they are quite cheap compared to transformers.
I don't want to join the outlets just want to make sure that i'm not over loading the transformer.
I realise that its 3A over the current rating for the Ceeforms but they are quite cheap compared to transformers.
As long as there is a fuse between transformer and collapsing insulation in the toasted Ceeform the transformer might not need replacing.
If there is one secondary winding feeding the two sockets then parallelling the two sockets will probably be OK.
BUT if there are two secondaries each feeding one socket then paralleling the sockets will only be safe if both secondaries have the same number of turns and thus give exactly the same voltage
Do you really think that a few minutes of passing 19A is going to melt a 16A EN 60309?
He's not planning to parallel them, just plug his grinder into one.
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You are looking at duty rating of the transformer with 110 volt transformers there is a huge variety from the yellow brick to the full duel MCB protected output in a box three times the size of yellow brick and twice as heavy which may or may not be centre tapped.
Protection also varies from a red 12.5 amp rated red reset button on the primary to 16, 20, or 32A twin pole on secondary.
When you open the lid some are encapsulated and sealed others are air cooled.
There simply can't be a one size fits all answer to your question. On some sites it's common to have a 20A MCB feeding two 16A sockets and plugging in a 19A grinder with 16A socket would work fine. In others the sockets have there own 16A MCB to every socket and with these the MCB will trip.
Some of the yellow bricks are very poor with a 12.5 amp trip not a proper MCB but just a thermal device feeding the input and you can draw 52A line to earth without tripping the trip or fuse.
The yellow bricks vary a lot some will over heat without being used the transformer is such low quality other are nearly as good as the tin box type.
Personally I think the risk of using a yellow brick with fire in mind exceeds the risk from a 230 volt RCD protected supply. The tin box with 16A twin pole MCB's on each output is great it just the yellow brick which have a problem. We will always get the extension lead plugged into extension lead and very quickly the resistance of cable reaches 1Ω at which point a short circuit line to earth will not open the 12.5A incomer trip but the cable can't take 52A so melts.
Protection also varies from a red 12.5 amp rated red reset button on the primary to 16, 20, or 32A twin pole on secondary.
When you open the lid some are encapsulated and sealed others are air cooled.
There simply can't be a one size fits all answer to your question. On some sites it's common to have a 20A MCB feeding two 16A sockets and plugging in a 19A grinder with 16A socket would work fine. In others the sockets have there own 16A MCB to every socket and with these the MCB will trip.
Some of the yellow bricks are very poor with a 12.5 amp trip not a proper MCB but just a thermal device feeding the input and you can draw 52A line to earth without tripping the trip or fuse.
The yellow bricks vary a lot some will over heat without being used the transformer is such low quality other are nearly as good as the tin box type.
Personally I think the risk of using a yellow brick with fire in mind exceeds the risk from a 230 volt RCD protected supply. The tin box with 16A twin pole MCB's on each output is great it just the yellow brick which have a problem. We will always get the extension lead plugged into extension lead and very quickly the resistance of cable reaches 1Ω at which point a short circuit line to earth will not open the 12.5A incomer trip but the cable can't take 52A so melts.
What ambient temperature applies to that graph ?
IHNI.
Probably either 30°C or 70°C.
Probably either 30°C or 70°C.
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I was asked to light some tunnels in Sizewell "B" power stations with 110 volt florescent fittings 60W each so decided to use 25 lamps on a 16A double pole MCB which tripped. When I checked they were drawing 20A where I had expected around 14A it was cured by moving tapping from 110 to 127 volt on first 20 lamps but as a result I know 20A will trip a 16A MCB and it did not take long around half hour for first trip and then 5 minutes maximum once warm.
Most the other jobs had 20A MCB's on the 16A sockets but Sizewell "B" was odd one out with 16A MCB's and we had large grinders and vacuum cleaners regularly take out the 16A MCB. With grinders we had to fit 32A plugs and with vacuum cleaners we used three phase 110 plugs. Two phases to each of three motors.
So it's not theroy it's practice I know large grinders will trip 16A MCB's.
They will also burn out the exciters on the Lincon Welding bullets and many don't like 110 volt DC either. We had to be very careful on the Pipe line jobs to get grinders with maximum of 10A and able to run on DC.
Latter bullets started to have alternators fitted special for the grinder but for many years the exciter was used for the 110 volt supply which was DC.
Most the other jobs had 20A MCB's on the 16A sockets but Sizewell "B" was odd one out with 16A MCB's and we had large grinders and vacuum cleaners regularly take out the 16A MCB. With grinders we had to fit 32A plugs and with vacuum cleaners we used three phase 110 plugs. Two phases to each of three motors.
So it's not theroy it's practice I know large grinders will trip 16A MCB's.
They will also burn out the exciters on the Lincon Welding bullets and many don't like 110 volt DC either. We had to be very careful on the Pipe line jobs to get grinders with maximum of 10A and able to run on DC.
Latter bullets started to have alternators fitted special for the grinder but for many years the exciter was used for the 110 volt supply which was DC.
Does it actually take 19A - or more or less ? And under what conditions ?
I would assume it'll take significantly more during startup, but once running I find it hard to believe it'll take a continuous 2kW. If it does, then the startup current could be "considerable" and could be a tripping problem.
That graph is not clearly labeled but based on my memory that the fast trip point of a B type breaker is supposed to be 3-5 times rated it appears to be a graph of maximum trip times.
Maximum trip times may be quite different from minimum or typical ones.
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