VFD outdoors, low temps --- bad idea?
VFD outdoors, low temps --- bad idea?
(OP)
We need to add braking on a motor, and Contractor has proposed VFDs. The make and model he proposes is Télémécanique Altivar 31C with an IP55 enclosure. I'm nervous because I've heard VFDs are very fussy about the ambient temperature they like.
The application is hoist motors, outside, on a dam (lots of ice in winter, constant wind, very cold down into the -20s Celsius at times). Contractor proposes putting them inside the existing electrical enclosure on the crane, which would at least get them out of the wind and spray although temperature would still be low. Note product datasheet says it's OK to -10oC but has no discussion of what happens below that. Enclosure is painted black and would get pretty warm in the summer (where we get up to the mid +30s Celsius with very high humidity). Product data says we'd be OK to +40oC and slightly "derated" above that, but I'm not sure what that means exactly.
Contractor swears he's installed these on other outdoor applications around here and they work fine. And for all I know he may be right. However, I just wanted to check with other folks who have VFDs outdoors in this sort of weather conditions. So, how are they holding up?
If VFDs in this environment really seems like a bad idea, what other options are there? Changing the motors to the kind with brakes, I suppose. Anything else?
The application is hoist motors, outside, on a dam (lots of ice in winter, constant wind, very cold down into the -20s Celsius at times). Contractor proposes putting them inside the existing electrical enclosure on the crane, which would at least get them out of the wind and spray although temperature would still be low. Note product datasheet says it's OK to -10oC but has no discussion of what happens below that. Enclosure is painted black and would get pretty warm in the summer (where we get up to the mid +30s Celsius with very high humidity). Product data says we'd be OK to +40oC and slightly "derated" above that, but I'm not sure what that means exactly.
Contractor swears he's installed these on other outdoor applications around here and they work fine. And for all I know he may be right. However, I just wanted to check with other folks who have VFDs outdoors in this sort of weather conditions. So, how are they holding up?
If VFDs in this environment really seems like a bad idea, what other options are there? Changing the motors to the kind with brakes, I suppose. Anything else?





RE: VFD outdoors, low temps --- bad idea?
I would also not take that at face value, I would ask Schneider directly and get it in writing. In my experience, they are notorious for telling you something verbally, then not acknowledging that when things go south later.
I took the liberty to look up an installation guide for the ATV31C, I found this:
But later on, it does say:
If you think there is a significant risk that someone will energize these drives when it is below -10C however, that would make it unsuitable.
Also, this drive does not appear to have an option for an encoder feedback, so as a general rule, I would not like it for a winch application. But on a dam, I have to imagine it's maybe a weir gate winch? That might be OK. But how much braking capability do you need?
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RE: VFD outdoors, low temps --- bad idea?
RE: VFD outdoors, low temps --- bad idea?
It is a misconception that high IP rating means it is suitable for outdoor mounting. You cannot go off the numbers but have to design it accordingly.
In NEMA/UL land, enclosure classification clearly identifies for indoor and outdoor.
A NEMA 3R enclosure is a relatively 'low' IP level but is designed to ensure moisture ingress and dust ingress as well as protection against sunlight and condensation with heaters that switch on when there is a temperature delta (typically) >10C.
I strongly advise against mounting an IP55 outside unless you have direct sun protection and some control on condensation build-up.
A drive rated at 40C means the ambient airflow through the drive is max'd at this level. Put a drive in sunlight and the internal temperature will shoot up.
I suggest you consult with a good quality installer and design it accordingly or mount the IP55 inside another enclosure away from sunlight and other nasties.
RE: VFD outdoors, low temps --- bad idea?
RE: VFD outdoors, low temps --- bad idea?
that is what most people do with a NEMA3R enclosure.
RE: VFD outdoors, low temps --- bad idea?