Does your VFD have a bypass?
You will need overcurrent protection if on bypass.
Help me settle a bet...When you have a tower with a remote VFD without bypass and need a line-o-site disconnect, what do you do?
1. Fused disconnect on output of drive?
2. Non-fused disconnect on output of drive?
3. Fused or non on input of drive?
4. Anything else?
Can you share why and such.....Thank you!
I can almost taste the prime rib.
Last edited by lipsoffurry; 04-18-2009 at 05:32 PM.
Does your VFD have a bypass?
You will need overcurrent protection if on bypass.
5 out of 4 people don't understand fractions
if the VFD is wall mounted it needs to be fused on the supplied house 3 phase with a disconnect,and a non-fused disconnect out on the tower.you can't use the key pad to secure the 3 phase off a VFD...ABB and others have that swing door disconnect that can only be in the off position to access the VFD wiring and inverted contactors and controls.
"when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY
Just remember to be careful when throwing the disconnect on the drive side of the VFD. A lot of drives don't like to be disconnected from the motor under power and reconnected.
How do I get my cut ?
I would put a non-Fused disconnect at the Tower, wait don't count your money yet! In addition I would install a micro switch on the disconnect so that the switch opens just before the disconnect blades open. Wire the micro switch to the "Safety Circuit/Contacts" in the drive so that when they open the drive goes "Dead" ! And I mean Dead ! Almost all drives have this feature, when that circuit is opened the drive totally shuts down, no coast, no ramp down, no power out of the drive.
There is normally a jumper on the safety circuit if no one has connected a fire system shutdown to it. The safety circuit may be 120VAC so install you wire accordingly.
The Micro Switch only needs to be rated 120VAC at 2 amps if I remember right.
Who ever wins I get half email my money to dontbetyourlife@loser.bux
If sense were so common everyone would have it !You cannot protect the Stupid from themselves !"Experience is the ability to recognize a mistake Before you make it again!" (Stolen Quote)
If I understand your question, the VFD is not at the tower location?
If its not, a non fused disconnect is required at the tower, reason being for emergency shut down! Not for service.
As Jema said, VFD's dont like to have their motors shut down while running. The Vfd should have a protected supply at the power source. If you need to perform a service on tower, shut down fan at the drive and lock it out. Then open you disconnect at tower for added safety.
"My hands are for sale"
We install non fused disconnect after making sure your main breaker is properly rated, if not then a fused disconnect should be used. regardless if the drive likes it or not safety and code compliance come first,(some of our drives our 3 or 4 floors from the tower) Install a non fused disconnect at the tower. I like the micro switch idea thanks CCI, for that one, all you need is a pair of extra wires a switch and your set.