Relays

T

tcrist

New member
There were a number of posts about relay problems and selections for Clearvue systems. My system purchased a few years ago came with a relay designed for a 30 amp draw. The 5 hp blower draws 20.8 amps at 240 volts when running but, unfortunately, on start-up it draws much more than 30 amps and soon the relay started getting stuck on due to welding of the contacts. I filed the contacts a number of times but that was only a temporary fix and I now am looking for a new relay. Clearvue is selling a Fasco H230B relay that is rated for 30 amps like my old one and when I checked Fasco's site they state the relay is only rated for 3 Hp at 240 volts. No wonder the contacts welded!

I suggest that Clearvue start supplying the Fasco H360 series of relays. These are rated at 60 amps and 7.5 HP at 240 volts and should provide a much longer life. Additionally these are a 3-pole relay that can be used for either 120/240 volts, single phase or three-phase current and are available in different coil voltages. My system is wired with 24-volt, remotely located activation switches so I can turn the DC on or off from numerous locations, kinda like a three-way switch for a stairway. See: http://www.fasco.com/documents/fascopage96-99.pdf

The initial start-up of a motor is almost like a dead short to the electrical system (that's why the lights dim) and the switches/relays controlling the motor need to be able to handle the start-up as well as the running current.

I hope this helps!

Tom
 
I bought my relay from Clearview 3 years ago and have yet to have a problem!

If your lights are dimming when you turn yours on then you have other electrical problems that need to get taken care off.
 
relays & HP rating

relays & HP rating

For what it is worth, There was a discussion on these relays some time back
http://www.clearvuecyclones.com/Bullentin/showthread.php?t=1174

The inrush current for the 5HP unit (60VA) is double that of the 3HP unit (30VA). They both have the same Full Load Inductive Amp rating of 30. You have to be careful of how often you cycle the unit. I think I had read that 5-6 times an hour is about max for the motor.

Not sure if your problem is related to the relay rating or something else.
As many have the original relay in service without problems, make sure you have no oter issues with your wiring. Of course there are a certain percentage of bad devices manufactured. You could contact Fasco a nd see if they would test relay if you replaced it. If found faulty, they should be able to arrange some form of credit.
There is probably a reason to not over spec the replacement. Get the one rated for a 5 hp motor. Still better to have the relay trip or fail than the motor.

Don
 
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Each component of the circuit must be rated to handle the expected load. Switches, wiring, circuit breakers and relays. A relay rated for a 3 HP motor should not be used to run a 5 HP motor. Only a shortened life expectancy can be expected. The better relay would be one properly rated for the motor size and for longer life in an application where the blower may get turned on and off frequently, an over sized relay would be the best choice. The cost savings for the undersized relay will quickly get eaten up when an electrician has to change the worn out part.
 
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