I bought a small vertical/horizontal mill about a month ago and got it into
my garage without too much excitement. It has a 2 hp, 3-phase motor for the
drive, and I bought it knowing I'd likely buy a VFD to drive it from my 220
volt service. (Buying a static converter doesn't make a lot of sense given
the loss of HP, and building/balancing a rotary phase converter isn't quite
up my alley and is going to take more space than a VFD. Also, VFD prices are
generally competitive with commercial phase converters.)

I've been primarily looking at the Teco FM100 unit at Dealers Electric,
having seen it mentioned on r.c.m. a number of times. However, my garage is
detached and isn't likely to be heated in this century. All the VFDs I've
seen specs for say that the ambient temperature shouldn't be lower than
about 10-15F (-10C). Well, that's true anytime between late May and early
October in my area (St. Paul, Minnesota).

I'd really like to use my tools year 'round (weekends mostly), and I'll be
installing radiant heaters over the lathe and mill for the cold periods, but
I don't want to keep them on all the time. (I may install contact heaters on
the mill and lathe and cover them with insulation to prevent rust.)

So I've been thinking about installing the VFD in an insulated box with a
thermostat-controlled heater to keep it at least within the spec'd range.
I'd think an insulated steel box for the VFD with a separate power-kill box
upstream would provide the safe and highly-visible way to turn off the VFD's
power supply.

Any suggestions for improving on this scheme? Any pitfalls that you can
think of?

Thanks,
Pete Bergstrom

"Pete Bergstrom" wrote in message
...
I bought a small vertical/horizontal mill about a month ago and got it
into
my garage without too much excitement. It has a 2 hp, 3-phase motor for
the
drive, and I bought it knowing I'd likely buy a VFD to drive it from my
220
volt service. (Buying a static converter doesn't make a lot of sense given
the loss of HP, and building/balancing a rotary phase converter isn't
quite
up my alley and is going to take more space than a VFD. Also, VFD prices
are
generally competitive with commercial phase converters.)

I've been primarily looking at the Teco FM100 unit at Dealers Electric,
having seen it mentioned on r.c.m. a number of times. However, my garage
is
detached and isn't likely to be heated in this century. All the VFDs I've
seen specs for say that the ambient temperature shouldn't be lower than
about 10-15F (-10C). Well, that's true anytime between late May and early
October in my area (St. Paul, Minnesota).

I'd really like to use my tools year 'round (weekends mostly), and I'll be
installing radiant heaters over the lathe and mill for the cold periods,
but
I don't want to keep them on all the time. (I may install contact heaters
on
the mill and lathe and cover them with insulation to prevent rust.)

So I've been thinking about installing the VFD in an insulated box with a
thermostat-controlled heater to keep it at least within the spec'd range.
I'd think an insulated steel box for the VFD with a separate power-kill
box
upstream would provide the safe and highly-visible way to turn off the
VFD's
power supply.

Any suggestions for improving on this scheme? Any pitfalls that you can
think of?

Thanks,
Pete Bergstrom



Think about putting a heater inside your VFD. You may also want to check to
see if there's a storage rating -- most electronics will survive storage at
(sometimes much) lower temperatures than the point where it will no longer
operate correctly. This _does_ depend on what they put in there, so you
want to check -- and remember that it's the insides that have to be up to
temperature when you go to use it (although that should happen fairly
quickly once you turn it on :-).

you might want to look at the Delta VFD (not THAT Delta, this is Delta
Electronics) - I have one and it has a nice keypad that can be mounted
remotely from the control box, and the box is a NEMA enclosure.

that said, you can heat the VFD if needed with a small light bulb - wire a
15 watt bulb across the 220 AC input - when you turn on the master breaker
for the shop, the bulb will light up and start warming the VFD. By the time
you get your frozen breath swept up and put outside, it will be warm enough
to fire up. If you are extra cautious, you could glue a thermometer to it
(I'd measure the temp on the heatskink, I suppose)

On this VFD (the one I have anyway) the fan only runs when it needs to. On
the one built into my wood lathe, the fan runs all the time. I prefer the
"only runs when it needs to" approach.

I have two teco drives and they both work fine.

I suggest you call dealers electric and ask them about the temp issue.
They will be able to get expert opinions directly from the manufacture.