new starters for old high mass fans

[blue_r1]

lately we have been running into alot of older fans buffalo forge, mcquay stuff 20-30 years old. i notice the older style fan starters will hold higher amps without tripping out while the fan is getting up to speed.
none of the new starters will do this without getting a much higher amp trip rating on the heaters, basically almost making them ineffective.
what have you guys been doing about old fans which are in good shape that need an entirely new starter assembly?

[powerhead]

Those newer "International" or "European" starters are cheap pieces of s%&#. They are made to exact tolerances and cannot take any abuse at all. You can't change the overloads, only "dial in" a small range of amperage. There is so little silver on the contact area that they won't last at all if you are just a little over on the amp or voltage rating.

I replaced one on an air compressor without knowing that the pressure switch was bad. When I started up the compressor the bad switch caused that IEC "contactor" to chatter. It only took about 2 minutes tops (I swear!) before it was toast.

Equiptment manufacturers love them because they are cheaper, take up less space, a smaller control panel enclosure is required and they do not have to stock a large variety of overloads.

Give me the old American NEMA motor starters and overloads any day which, by the way are still found at most supply houses. (But for how long?)

[powerhead]

Whoops,
Spazzed out on the clicker!

[Edited by powerhead on 02-08-2006 at 07:48 PM]

[scott123]

One answer: VFD's

Brand of VFD = ABB

Problem solved

BTW...IEC requires IEC fusing (J-Type). Standard NEMA style fuses, servicing an IEC device = dangerous

[Edited by scott123 on 02-08-2006 at 08:29 PM]

[blue_r1]

frequency drives are the best replacement saving costs of belts, drives, and peak electic billing over a period of time but the initial cost is what kills the deal. we are talking fans that are 20-30 years old, most of these motors are not even rated to run with a vfd so most likely the motor will also need to be changed. old school motors last forever and can take a huge amount of punishment vs. these new motors that have the hp rating but 1/4 the life span if that.

if a building has something that is 30 years old on site, chances are they already know how much it will cost them to replace the entire unit out already and are just milking ever last hour out of it, so limited funds will be available to do repairs anyway churches, schools and "slum lord" builings are the worst.

we do so many surveys on entire buildings, very thourough and come up with a package of replacement cost/ lifespan of whatever equipment might be there. no matter what the total cost of replacement or repairs is, the question always asked is how much will it cost me to get thru the year

i am shocked when we get a new survey done and the owner is like ok fix it all. rarly happens now.

[scott123]

Depends on the HP of the motor. VFD's are getting more cost effective every year, even if a motor replacement is necessary. I've seen rather large fans that were 30 years old (motors as well). Years later the old motors are still running fine. Up to 100 HP there is really no other option. A Y-Delta, Auto Transformer, or part-wind starter is a very expensive venture. I still say go VFD because short of replacing the whole thing there really isn't anything more cost-effective.

[ccv2]

If not being used on a system requiring variable air flow a vfd is overkill. Soft starters have come down in price and are used on a wide range of horsepowers variable or constant torque applications with excellent results.

[al o]

furnas/siemens have a what I believe is a series 20 electronic overload that allows for the high start up current. you can just install the overload block & leave the contactor in place.has exelent single phase protection

[Edited by al o on 02-09-2006 at 08:11 PM]