Hi
Does anyone have figures for the actual power taken from say a 1HP motor for the average sized workpiece?
Perhaps someone with access to a clip-on ammeter could do some checks. I'm pretty sure it would need a big piece of wood and a heavy cut to reach full load.
At our club's tuition sessions we sometimes have all our nine lathes in action.
Tony Malin
Hi Tony,
One horsepower in modern parlance is 750 watts, and most motors are referenced by their input power, not the physical output. On that basis the maximum input current would be 750/240 Amps, so 3.125 Amps. However, I am guessing the point you are trying to establish is the current under certain loads which is almost impossible to determine unless, as you suggest, you put a meter in line. But you should be allowing for worst case scenario. I would certainly not be trying to allow for nine lathes working off a single 13A supply. Allow 4Amps per lathe and you should be ok. But now you need to check the ring main supplying those sockets. Old wiring used 2.5mm cable, capable of supplying up to 21Amps TOTAL, newer wiring uses 4mm cable and will be rated at 30Amps. In either case, you have capacity for nine lathes, even under heavy load.
Whatever you do, please avoid using multiway adapters. Each lathe should be plugged into its own 13A ring main socket. If you have to use multi-sockets, make sure they are very high quality and are rated at 13A. Most are only 3 or 5Amp. That's where most people come unstuck and create a fire hazard.
And of course bear in mind that the initial start current can briefly exceed the running current. That is one reason an inverter's limit is set in excess of the 'normal' value. Mine are set at 6A, well within the limit of the supply but ensuring there is enough power to get the wood moving. But I only have two lathes at most, running at the same time.
Hope that helps,
Paul
