Ian Barley
03-20-2004, 4:01 PM
I need some help with electrical math. I know that there are some experts watching here so I throw myself on your mercy.
I have the potential to bid (good old ebay) for a big thicknesser. This is a 5hp, 415V, three phase machine which I will be running through a phase converter/transformer from a 230V single phase supply.
My problem is that my electrical circuits are not all that special. Basically the whole caboodle runs off a 63amp breaker (15KVA??) and my main circuit is a 32amp ring, which I would hope to run this machine off.
Now, I know that I should have been paying attention in physics class - but I didn't. I think that a 3hp single phase motor draws about 2.25KW @ 230V - give or take thats 10amps
I guess that this means that a 5hp motor running in the single phase will draw about 3.75KW - give or take thats 16 amps.
Now I know that the phase converter will not be 100% effecient but I am also assuming that it will output abou 70-80% of what it has as input. Does that mean that this 5HP machine will require a braker of about 20amps at 240V?
The more I think about this the dumber I feel but I really don't want to end up with a 1200lb boat anchor by buying a machine that I cannot run - help!!
I have the potential to bid (good old ebay) for a big thicknesser. This is a 5hp, 415V, three phase machine which I will be running through a phase converter/transformer from a 230V single phase supply.
My problem is that my electrical circuits are not all that special. Basically the whole caboodle runs off a 63amp breaker (15KVA??) and my main circuit is a 32amp ring, which I would hope to run this machine off.
Now, I know that I should have been paying attention in physics class - but I didn't. I think that a 3hp single phase motor draws about 2.25KW @ 230V - give or take thats 10amps
I guess that this means that a 5hp motor running in the single phase will draw about 3.75KW - give or take thats 16 amps.
Now I know that the phase converter will not be 100% effecient but I am also assuming that it will output abou 70-80% of what it has as input. Does that mean that this 5HP machine will require a braker of about 20amps at 240V?
The more I think about this the dumber I feel but I really don't want to end up with a 1200lb boat anchor by buying a machine that I cannot run - help!!