VFDs out in the cold
- Thread starter soundmind
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John Wilson
Well-Known Member
A great solution for the unenclosed VFDs is an old ammo can. You can always punch some holes in the bottom and put air filter material over the holes. That will get you nearly spray-tight, or IP66/67.
In most shops, putting the VFD several feet away and running the speed pot to the grinder would solve 99% of the dust problem if you have a dust collector on the grinder or a good bucket system.
I have the KBAC27 (NEMA 4x) with packing glands, but I’ve also got it mounted directly to the grinder so that I can reach the controls easily.
When I eventually put a VFD on my lathe and drill press I’m using a cheap Chinese VFD without a second thought.
In most shops, putting the VFD several feet away and running the speed pot to the grinder would solve 99% of the dust problem if you have a dust collector on the grinder or a good bucket system.
I have the KBAC27 (NEMA 4x) with packing glands, but I’ve also got it mounted directly to the grinder so that I can reach the controls easily.
When I eventually put a VFD on my lathe and drill press I’m using a cheap Chinese VFD without a second thought.
Actually the Chinese VFD enclosures are rated. They are rated NEMA 1, which is open. I mount cheap Chinese VFD units right on the grinder, but do use an inlet filter over the air inlets to filter metal dust. I did have one chinese drive fail after about 5 or 6 yrs, but not sure it was dust inside. When I took it apart there wasn't any visible dust, but that's not saying it wasn't there to cause the failure. I've been running a NEMA 1 VFD drive on the lathe which is mounted 10 ft or so away from grinders and it's been running for 8 yrs now.
Gliden07
Well-Known Member
I bought a cheap Chinese one for a disk grinder I'm building. It's open but this grinder is being built on the cheap! I paid more for the HF tool stand than the rest of the parts for it!
I got a whole caribou for Christmas one year. I was thinking man, around here if Santa showed up on the roof someone would probably grab their rifle and take a shot at one of his reindeer.
The other thing too about moving south is I'm scared of snakes.
You know my smartphone has lasted 7 years. But I wonder if some kind of electrical spray would be good to spray on the circuit board VFD. On the other hand I don't want to mess with the circuit board at all. And they are probably already are have a corrosion resistant coating.
My other thought, similar to John's, as an inexpensive solution was to build an insulated box or tent over the VFD and keep a light bulb on inside it.
Eaton makes a VFD for cold temperatures (power xl). I was hoping KB did or a fan/heater combination.
I'm still learning about them the past couple of days. It surprised me VFD's are everywhere in industry. A roof is the last place I'd expect there to be one, hot or cold.
The other thing too about moving south is I'm scared of snakes.
You know my smartphone has lasted 7 years. But I wonder if some kind of electrical spray would be good to spray on the circuit board VFD. On the other hand I don't want to mess with the circuit board at all. And they are probably already are have a corrosion resistant coating.
My other thought, similar to John's, as an inexpensive solution was to build an insulated box or tent over the VFD and keep a light bulb on inside it.
Eaton makes a VFD for cold temperatures (power xl). I was hoping KB did or a fan/heater combination.
I'm still learning about them the past couple of days. It surprised me VFD's are everywhere in industry. A roof is the last place I'd expect there to be one, hot or cold.
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John Wilson
Well-Known Member
VFDs make the world go round.
ba duh bump! tip your waitresses...
VFDs revolutionized industry. Before that if you needed speed control it was all DC motors and controllers or you used hydraulics. And yeah- putting them on the roof to save room in the machinery spaces was a pretty bad idea. I’m sure it seemed like a good idea at the time.
Ken thanks for clarifying that about dewpoint. If I can understand that, it'll help me other ways too.
Besides condensation, the other problem I found (repeated on different sites) was that the capacitors would freeze, then explode (maybe pop/leak) when power was turned on. I should have mentioned that too in my first post. It does also seem like reliable information to say the have an operating temp -10c to 40c. I hope my VFD comes with a manual when it arrives as this might be referring to a different drive. I can post the links if anyones wondering what I'm reading.
Besides condensation, the other problem I found (repeated on different sites) was that the capacitors would freeze, then explode (maybe pop/leak) when power was turned on. I should have mentioned that too in my first post. It does also seem like reliable information to say the have an operating temp -10c to 40c. I hope my VFD comes with a manual when it arrives as this might be referring to a different drive. I can post the links if anyones wondering what I'm reading.
I bet they're on equipment up on the slope. I wonder if AKwildman has any thoughts?
When the weather is that cold it's beyond my comprehension. I live on Gulf Coast, when temp is forecast to hit 32F the news is all over about freeze warnings and how drastic the cold is going to be, get pets inside, wrap pipes, etc. To me, a capacitor freezing is like spit freezing and cracking before it hits the ground - doesn't that take place somewhere around -40F? That is the one place F is = to C, -40F = -40C.
Soundmind, to a simple old country boy like me your screen name "soundmind" is an oxymoron considering where you live. How can anybody be of "soundmind" and live in rural Alaska? Of course, other folks would say the same about me, how can you live with all those hurricanes? Now I live on land at 100 ft above sea level they're nothing compared to the 25+ years I lived on a boat and had to ride out hurricanes anchored out.
I don't like cold, that's why I live South of I-10 hwy.
John Wilson
Well-Known Member
Yeah that is some serious cold. If I expected cold of that magnitude I’d wire a low wattage lightbulb to stay on inside the electrical enclosure. It wouldn’t take a whole lot to keep a sealed enclosure above the point where caps would freeze. You could power it directly off the terminal strip on the VFD’s power board.
Rick Otts
Well-Known Member
Yes I agree Ed is very helpful he has always answered my Emails.
For me it's heat - at least humidity and heat. About three years ago I remember driving from Arkansas to CA and intentionally drove north to HWY 80 for the ten degree difference in temperature than what was forecasted along the more direct southern route. And your right about hurricanes. I also lived in SC for a few months in '14, had a storm scare there, and seen tornadoes coming strait at me in MO. I couldn't imagine riding out a hurricane out in the water. Hats off to you. LOL all that combined with snakes - man, I was done. You might enjoy it out here in the fall. Don't try summers in the bush unless someone pays you, too many mosquitoes.
That sounds good. I'll take a look at it when it comes. I should see it here hopefully the end of this week or next week.
It would be that kind of temps. even a rare -65. I don't mind bringing it in the house, but I'd rather not have to even move it at that temp. Anyway, I'll know more when it comes. Thanks everyone for the feedback. I know its a more extreme thing but was wondering what else was going on real time.
John Wilson
Well-Known Member
By the way, I never turn my VFD off. It got powered down once 4 years ago when I moved to my current house. The board has had power on it continuously all that time. Well, I take that back. Originally I lived in a condo with no 220 in the garage so I had it on a long cord. I plugged my grinder into the clothes dryer outlet when I wanted to use it. When I moved to my current location 4 years ago I wired it up and it’s never been off unless the power went out.
Keeping the main board powered up keeps it warm enough to keep the humidity out. Would that be enough to make up for the extreme cold you are talking about? That I don’t know. Ambient here never gets much below +40F and that doesn’t last. It was 80 today. (December)
Keeping the main board powered up keeps it warm enough to keep the humidity out. Would that be enough to make up for the extreme cold you are talking about? That I don’t know. Ambient here never gets much below +40F and that doesn’t last. It was 80 today. (December)
From what I've read so far, I think so. I still want to talk to the people who make and/or sell them, too.
I'm working on this and realized what you're saying. By powered up you meant keep it 'on.' Initially I thought you meant leaving it plugged in. I got online about to post my idea and it was what you already had said. Thanks John.
I had another idea, too.
The baseplate that came with the grinder has a lot of mass. Its a solid piece of 1/2 plate. That seems like an efficient heat source if I can warm that up. It's -50 now so this was my chance to see how the wheels would turn in sever cold. They're a little sluggish. The whole thing would need to be warmed up before use in order to take good care of it.
Which will also mean the motor, too. I think keeping power to the vfd will work most of the time. But I'm going to still build an insulated box for the whole grinder and all components for the more severe temperatures. I've built homemade coolers for people to get fish/meat home using spare insulating foam board. One of those made it 36 hrs in transit to Ohio summertime. I think that'll be the way to go. I realize I don't want to always be taking the wiring back down after every use in the winter. I'd like to leave it as is.
Thanks again everyone for the help. It's "my new baby" and is going to take some figuring. I appreciate your input.
"If it's worth the going, it's worth the ride."
So I went with a heat tape wrapped around the outside. I wrapped it right around where the circuit board is. The tape and the metal in that area are warm. But the door is still cold.
What I'm wondering and why I quoted you Ken, was this: I wondered if I was actually creating moisture by forcing heat on it. If I was actually creating a warm and cold air meeting inside the vfd and forcing a "dewpoint" by not heating enough of it at one time.
So I was wondering if you could help me understand something about humidity and dewpoint. Not sure if it's from your boating experience or living in the south, but I thought you might know.
I noticed frost on the spark plug wires on my snow machine the other day and know it was due to cooling, not warming up. On the other hand, I get water on anything steel when I bring it in from outside. That's from warming up. Same thing with frost on metal outside and carburetors icing after a spell of sub-zero and it warms up to about 0 - 20 above. And that's where I really get my question from. Maybe this is better in a PM.
It was -40 last night. After going to bed thinking about this, I opened it up this morning to have a look. I felt warm air inside and didn't see any frost anywhere, so I'm good for now. I just wondered if I was turning my VFD into an environment too close to the freezing/melting temperature. But like I said we get frost below 32 degrees.
Thanks, Luke
Luke, It's so hard for me to comprehend temperature of -50F (almost same as -50C) there's not much point in me trying to recommend anything. Do remember at those minus temperatures there not much moisture at all in the air. I'm sorta of the opinion you're worrying too much about nothing. Warming the VFD will keep the electronics warm, and any air that comes inside enclosure at -50 isn't going to have any moisture in it. That's one way we dry air - get it cold!
If you're worried about the electronics then purchase a cheap Chinese VFD for $60 to $70 to use. After a few yrs you can see if there's any corrosion issues. If the corrosion gets the electronics you've not lost much. With an air filter over the air inlets under normal hobby use I'd expect the NEMA 1 VFD to last several years - depending if any corrosion issue.
If you're worried about the electronics then purchase a cheap Chinese VFD for $60 to $70 to use. After a few yrs you can see if there's any corrosion issues. If the corrosion gets the electronics you've not lost much. With an air filter over the air inlets under normal hobby use I'd expect the NEMA 1 VFD to last several years - depending if any corrosion issue.
John Wilson
Well-Known Member
Luke, of all electronics in the world VFDs are as tough as they come. Some little bit of condensation is not going to hurt anything. These are industrial devices, not lab equipment. They will take a fair amount of abuse and are used in pretty austere environments.
Like Ken says- start with a cheap one and see. The NEMA 4x ones aren’t sealed for fear of condensation. They are sealed for industrial food manufacturing where equipment must be washed down with foaming disinfectant and blasted with hot water as a sanitation requirement for food processing equipment.
Please don’t overthink this. Every oil rig and drill platform in ANWAR and the North Sea is running VFDs.
Like Ken says- start with a cheap one and see. The NEMA 4x ones aren’t sealed for fear of condensation. They are sealed for industrial food manufacturing where equipment must be washed down with foaming disinfectant and blasted with hot water as a sanitation requirement for food processing equipment.
Please don’t overthink this. Every oil rig and drill platform in ANWAR and the North Sea is running VFDs.