nm145 surge protector

[bob b]

what do you guys recomend for a surge protector for nm145

[Frogblender]

+1

My NM135 does the following:
1) Puts a huge amount of EM crap back onto the 120VAC circuit, judging from the fact X10 stuff doesn't work if the mill is turned on.

2) Is susceptible to other devices putting crap onto the mill's 120VAC circuit. An anti-static ion generator being turned off/on on the same circuit causes funny mill behaviour: 1) sometimes a e-stop, and/or, 2) if the mill is not moving, a big fat clunk. Extremely annoying.

Isolation would be good. Any ideas?

[JoeBean_NEW]

+1

My NM135 does the following:
1) Puts a huge amount of EM crap back onto the 120VAC circuit, judging from the fact X10 stuff doesn't work if the mill is turned on.

2) Is susceptible to other devices putting crap onto the mill's 120VAC circuit. An anti-static ion generator being turned off/on on the same circuit causes funny mill behaviour: 1) sometimes a e-stop, and/or, 2) if the mill is not moving, a big fat clunk. Extremely annoying.

Isolation would be good. Any ideas?

Measure or calculate the ACTUAL load of the machine. If you have an AC clamp-on ammeter use that, or a power meter. Worst case scenario you can take the 15A 120V recommendation for circuit size from Novakon, take 80% of the current load (12A - 80% loading of a circuit is max allowable, not saying they followed that though, but they did over-estimate for the NM-200 so the NM-145 is likely similar) which will give you 120*12=1440VA. So get a minimum 1500VA true sine wave UPS. A standard square-wave UPS would probably work too, but a sine wave unit should definitely work. Calculating the actual peak loads may allow you to buy a smaller (and thus cheaper) UPS. They are typically rated for up to 125% max load for brief periods.

This way your equipment is isolated. I've used sine wave UPSs for other machinery with success in the past. Plus, if power goes you won't just crash dead, you'll have a few minutes to shut things down.

APC aren't bad. Not cheap, though. Cyberpower is somewhat cheaper.

[ihavenofish]

keep in mind that while the "motor issue" is going on, it is drawing far far less current than it will be later on, especially at the lower speeds. so if you measure it and it seems oddly low, it is, and you shouldnt size the ups/surge suppressor on that number.

[bob b]

is all i could find was a 15 amp 120 vac 1800 watt i will give it a try for now

[JoeBean_NEW]

keep in mind that while the "motor issue" is going on, it is drawing far far less current than it will be later on, especially at the lower speeds. so if you measure it and it seems oddly low, it is, and you shouldnt size the ups/surge suppressor on that number.

VA=W/Power Factor. Assuming 60%, you have about 1800W. Likely it's better than that.

[ihavenofish]

VA=W/Power Factor. Assuming 60%, you have about 1800W. Likely it's better than that.

on my 145 its more like 15-25%

[bob b]

so do you think it will be heavey enough or not ?

[ihavenofish]

so do you think it will be heavey enough or not ?

no.

the steppers are 5.5 amp 70 volt if i recall, so thats going to be up to 600W for them to be safe. then you have the computer. thats a good 400W counting an lcd if tis plugged into the side panel. then theres the spindle, which should be 1500+w peak draw on its own when they fix the driver.

so unless you split things out, you need more like 20-25 amps. and yes, thats a bit more than the typical home circuit provides.

its a tricky thing though, since its very rare for all items to be drawing full load at the same time. this is why measuring the true load in real conditions comes in, but you wont get a good idea of that til the spindle works.

me, id be tempted to split off the spindle power to an unprotected source, and only back up the more delicate electronics.

[JoeBean_NEW]

on my 145 its more like 15-25%

No it's not. At least at peak it's going to be nowhere near that. If it were you'd need an 80A breaker and massive feed wiring, as the apparant power would give a (1100/.15)/120=61A draw.

If you look at specs for UPS's virtually everyone says 1500VA or 1800VA units, depending on the max size they sell, are max for a 15A. Which is obvious when you consider that 15*120=1800. With a UPS you have to take into consideration losses/pf in the unit and pf in the load, but a decent quality unit will handle this machine. BLDC typically has a decent pf.

As I mentioned before, reading the apparent power by measuring current draw is all that's required to size this.

[ihavenofish]

No it's not. At least at peak it's going to be nowhere near that. If it were you'd need an 80A breaker and massive feed wiring, as the apparant power would give a (1100/.15)/120=61A draw.
.

sorry, i think we misunderstood each other. i mean if he measured the nm145's power as it is NOW, its only about 20% of what it *should* be, making the reading useless.

[Frogblender]

Buy a power meter (they are cheap and useful), and you'll have real data on how much your mill draws:

Power Meter

My NM135 draws around 700watts or so (can't remember exactly) when it is working at full speed (this includes the controller box and the mill itself, but not computer&monitor). This 700W is with the spindle lightly loaded (1/8" bits in 6061); if I was to machine titanium with glowing chips, it'd be more.

Also, startup motor surge currents for the mill are much much less compared to say, a compressor motor, as the mill has intelligent VFD & stepper controllers full of electronics and current-limiting stuff, whereas the compressor has nothing but heavy copper between the motor coils and the AC mains.