As you can imagine we get quite a few questions submitted by our website ( & visitors. And as always we answer all questions. Below are just a couple questions we received this week and the answers we provided.

Q. We are a distributor in the food service industry in Atlanta, GA. We provide exhaust and supply fans ranging from 1/4 to 10 H.P., we are looking into providing Variable Frequency Drives to our customers so they can control the speed of their fans. Can you provide us with any pricing, availability, and product suggestions for our application? Thank You.

A. Thanks for contacting Joliet Technologies. Be glad to assist…

As long as the fan motors are 3-phase, the selections are numerous and drives are readily available. However, if the fan motors are single phase, I do not have a drive I can quote you. Single-phase output drives are exceedingly hard to find; I am aware of only one manufacturer, and we do not supply them because the torque output of the unit is ridiculously poor.

If it is 3-phase you are looking for, there are numerous brands/options available. The horsepower range you are requesting is large and I cannot quote every drive in the range, but I can quote “high and low end of the range” units. Note also that many drives up to about 5 hp will allow a single-phase input and provide a 3-phase output; in some installations where only a single-phase input exists, it makes sense to change out the fan motor to a 3-phase model – you get better operating efficiency, they are easier to replace, and better control. All depends on the size of the motor and how difficult it is to get at. Cost for the change is often offset if you are able to reduce fan speed; for example, if you reduce the fan speed from full to 80%, you’ll get a reduction in energy use of almost 50%.

So assuming the drives can be mounted indoors, within a protected location where the ambient temperature doesn’t exceed 40C (104F), and are within 50 conduit-feet of the motors themselves, a couple of quotes are as follows:

1. ABB 1/2 HP drive, 1/60/240V input, 3/60/240V output, 2.4 amps, for panel mounting: $160 + freight. Adder for NEMA 1 kit for stand-alone wall mounting: $48.
2. Yaskawa 10 hp drive, 3/60/240V in/out, 30 amps, NEMA 1 encl. std.: $710 + freight

As noted above, there are other options as well. For up to 1/2hp, I can also get drives rated for 120V input (still must have a 3-phase 240V output, tho). These tend to be maybe 5% – 10% more expensive than the 240V units, because they need to beef up the converter sections. In any case, we can also adjust pricing to provide discounts for quantity purchases as well. Particulars will depend on the drive and manufacturer selected. Once you are able to provide specific horsepower and amperage requirements and quantities (if applicable) I can nail prices down further.

Some data for each drive quoted is attached. If you have any questions/need more information, please contact me.

Thanks –
Jay Baima

Q. I have a Lenze AC Tech SCF series drive that will not turn on. I check the fuses and they are working fine. The LCD display doesn’t turn on at all. What is the best way to check if I will need a new unit?

A. Check power input at L1/L2/L3 connections (drive input). If power there, but you have no display/can’t use the drive, then either your control section or power section is shot. Because these drives are so inexpensive, no one repairs them; it’s just not cost-effective. If you want me to quote a new one I can; just need the full model number of the one you have.

Jay Baima

If you have concerns or questions about any of the above, please let us know by visiting our Comments section, or contact us at or visit us at and We’ll be glad to assist. And please join me in a couple of weeks for another column.

As always, thanks for reading –

Jay Baima - Author

Jay Baima
Joliet Technologies