Variable frequency drive control options

[sbradt]

I am looking to set up our new brewhouse with VFDs for several of our pumps. All of the drives that I've seen, including the one in use at our current facility, have the speed control pot as an integral part of the whole controller. I would like to be able to locate all of the controllers (i.e. the motor starter/thermal overloads/frequency drive units) in one location and simply wire speed control pots and on/off switches to the points where I would like to have the controls. This allows me to put the controllers in a centrally located, well ventilated (cooled) cabinet while keeping the actual speed control where I need it. Does anyone have any suggestion for where to look for this type of controller?

In case I'm not being clear, here's an example:
My wort pump would have a VFD, located near a central breaker panel in a well ventilated electrical enclosure. I would like to place a simple potentiometer, "pot", type dial control ( or even a digital control) at the point of use, 20 or 30 wire feet away. Presumably, I would also need an on/off switch of some sort at the point of use also, rather than just dialing the pot back to zero to turn the pump off.

The reason for this approach is that I'd like to keep the heat down around the VFDs and I don't want to have to put in separate, ventilated enclosures for each one, especially in a rinse-down area.

Thanks,

[MJT]

Most modern VFD's have terminal blocks available with integral power enabling you to wire pots, stop/start/ and speed step control in remote locations. Also, these drives will have the built-in PID tuning necessary to automatically control more critical processes, such as controlling recirc during sparging. A third benefit is that these same drives will have built in comm ports(RS232/RS485/MODBUS) with the option of adding ethernet/devicenet/etc. control options so you can use HMI's/digital readouts/network to pc- the sky's the limit.

That being said, Allen Bradley Powerflex series is a nice albeit expensive option for a small brewery. Since it is not a very complex operation, go to http://automationdirect.com and you'll pay half the price and get the same result.Plus, if you order the drives today, chances are they will be to you in a day or two.

Good luck!

[grs]

What MJT said...BUT be aware that some drives may have the terminal block for remote start/stop and speed pot as an option - not included in the base drive. Also, some vfds have an option to locate the programming/local control board remote up to a certain distance. Post what type of drive you're looking at and we can help.

As far as the actual control panel, any electrical contractor should be able to get you a Hoffman enclosure and punch a couple of holes in it for some control buttons and a speed pot.

[gitchegumee]

I bought a 1HP 3 phase drive from Rob at Premier Stainless for $275. It's an Automation Direct unit. It has an optional 3 meter cable that I bought to remotely mount the keypad into a control panel. It works great! Can't say the same for the A-B stuff we used to own. I installed the ventillated unit above the washdown area where it wouldn't get hosed down. Simple, effective, cheap.

[Larry Horwitz]

Hey Steve!

the design you're talking about is what Specific does for us. The VFDs etc are in a remote box and the pots are on the front of the brewhouse. We've got allen bradley VFDs and the book shows how to wire them up. they just need to be put across the correct poles in the VFD and then you've got to change a few of the paramaters in the units. I think ours run on a 24v line and they were very easy to replace the last time the fried (they're always getting wet as you'd imagine) i can send you a scan of the wire diagram if you think it'll help.

cheers

[Alley Kat]

We had a similar issue here; we wanted to operate a pump in our cellar from our filler. We used a Hitachi (L300?) VFD and connected it to a remote operator station with a cat-5 cable. The cable run in about 50 or 60 feet.

Cheers!
--Neil