Spal fan wiring questions

[Efi69Cam]

Has anyone wired dual Spal fans in the series/ parallel arrangement with three relays for two speeds with both fans going at the same time?

[jwillia2]

I just went through this

[Efi69Cam]

Thanks for the diagram, its easier to decipher than the service manual.

Have you run spal fans in series? What I'm a bit concerned about is whether or not the motors are good running on 6 to 7 volts.

[jwillia2]

Originally Posted by Efi69Cam

Thanks for the diagram, its easier to decipher than the service manual.

Have you run spal fans in series? What I'm a bit concerned about is whether or not the motors are good running on 6 to 7 volts.

i don't see any issues. also they made a variable speed controller for their fans thats doing the same thing. just reducing the voltage to slow them .

[roger1]

Originally Posted by jwillia2

i don't see any issues. also they made a variable speed controller for their fans thats doing the same thing. just reducing the voltage to slow them .

PWM controllers like the Spal sells don't reduce voltage to control motor speed. Pulse Width Modulation is a controlled high speed switching control that varies the amount of on/off time (pulse width) to the motor.

That said, I don't believe lowering the voltage to a brushless DC motor reduces it's life. Like has been pointed out before, GM used a series/parallel system for 2 speed operation for may years.

[130fe]

Does anyone have a good schematic for wiring in 2 fans (with PCM fan triggers) and a trinary switch using 3 relays?

[Larry R]

This schematic is the way my two Spal fans are wired. I am using two engine mounted temperature switches of different values to operate the fans; lower temperature controls series wiring and higher temperature controls parallel wiring. I don't see why one couldn't substitute a PCM source in lieu of the two temperature switches. This system works well.