How to create a 32A 110v supply?

[the snooper]

The heating element could very easy be run off 230v and the fan might have to be 110v.

what fan there isnt one

 

[dannyp]

got a coupel of those type heaters, diffrent make but same thing.

a 3.3 kva will not like been left running it, thermal cutout will kick out regualy if you have both tubes on. a 5Kva will run it happily as for the plug may as well just do what everyone else dose and puts a 16A plug on it


but really if it's just for garage use by you just convert it to 230v ether by moveing wires inside or changing the tubes.

i modifyed mine to be dual voltage. cost a ew quid in switches and bits but was worth it to save buying more heaters or getting transormer for 110v at home

 

[awemawson]

Theoretically if you put a large diode in series cutting out one half of the mains sine wave you will bring the power dissipated on 230v back down to what it was at 115v

 

[mm289]

So, simple approach (save spending more money) lets wire it as 240v single power.

Hope this isn't too dumb a question, but what do i need to do to switch it to 220v?

Cheers,

MM

 

[the snooper]

just wire in series

 

[mm289]

Thanks for that guys, will do just that

Will the original heater bars/filaments be ok, no need to swap these?

And for the technically minded amongst you..........
why does the amperage needed drop so much going to 220v i.e. running at 110 draws 27A or something yet at 220 I can run off a 13A?

Many thanks,

MM

 

[tigler]

It's all down to Ohm's law. Current is determined by voltage and resistance, resistance of the heating elements in this case. Example, for a given voltage, if the resistance is doubled the current halfs and vice versa. The formula is I (current) = V (voltage) over R (resistance). Ohm's law states, the current flowing in a closed circuit is directly proportional to the voltage as long as the resistance remains constant.

 

[rtbcomp]

It's all to do with power. Power = volts x amps, so to get a given power at 220 volts you need half the current than you would at 110 volts.

So if you have one 1.5 Kw bar at 110 volts it draws 1500/110 = 13.63 amps, connect two in parallel you're drawing 27.3 amps.

But if you connect them in series across 220v each still has 110 volts across it, so the current through each is still 13.63 amps. Because they're in series the total current in the circuit is also 13.63 amps.

 

[Pete.]

I dunno how much they cost but our comapny kits every van out with a 5kva transformer, that just has a 13A domestic plug on it. Many, many times I have had my 3.3KW drill motor AND a 1500W hoover running off it at the same time for hours on end.

 

[mm289]

Thanks for the physics lessons chaps

I did this stuff at school but it was rather a long time ago

Understand now, and also answers the Q about are the heater elements OK to use - yes because they are in series each is still only drawing 110v and total current is still 13

Awesome stuff

Maybe my "cheap" heater wasn't such a bad buy after all

MM