hd520 power draw

[mhgumbyd]

has anyone put a watt/amp/volt meter on the cord that powers their 520? I have a 520 w/ 3hp spindle, all on one circuit as they say all it needs is a 15amp circuit (owners manual). I put one on mine to check the load on the circuit. Voltage is perfect, but with it running and cutting (19,000 rpm) the whole system is drawing less than 7 amps. That doesn't sound right to me.

[NathanAu]

Sounds like you maybe getting only half the amps on whatever meter you are using? If you are using one of those clamp on amp meters, you need a splitter than can go around just one the wires because just clamping around a regular cord with both the hot and neutral cancel each other out. You can buy a amp meter splitter on Amazon or just make one using wire strands and a pair of male and female plugs. The ones you buy often have multipliers to give you better accuracy (just divide the result by the multiplier). You can find plug-in meters such as the Kill-a-Watt that you can simply plug into but they may only be limited to 15 amps? Also, the 3HP spindle should be 2.2kw which on 115v would be 19 amps at full power not counting the HD520 control box and VFD needs. Most 3rd party 2.2kw spindles I have researched suggest that you need a circuit that can handle at least 25 amps at 115v so you would probably need a circuit capable of 30 amps with appropriate gauge wire and 5-30R receptacles. If NW is saying that this works on a 15 amp circuit, it makes me wonder if they are constraining the speed or something? I went with a 3rd party spindle because I do not have a control box that can control a spindle anyway and was about 1/4 the cost to upgrade through Next Wave. I went with a 240v model because it can run on a 20 amp circuit which was easier to add to my shop breakout panel to run a dedicated power and plug to my CNC's location.

Note that this forum shuts down on March 16th and I may not be available for the next several days but I hope my input is helpful.

[mhgumbyd]

I'm using a plug-in meter. meter plugs into the outlet, cord to the machine plugs into the meter.