PDA

View Full Version : fan reversal



Temprite
07-12-2004, 09:55 AM
Anyone know how they reverse the single phase motors during the off cycle on some ice cream cabinets and cases to keep the condensers clean.
Fan motor was single phase and normally had no capacitor on it.but in this case a run capacitor was wired in parallel across the active and neutral.
If you swapped the active and the neutral the fan runs the opposite way.
Regards

Temprite
07-12-2004, 11:52 AM
G'day Mark
I might be missing something here but don't you need access to the start of each winding?There should also be a wire for the common.So in total the fan motor you are talking about has 3 wires and an earth.I have reversed several of those fan motors before.
This fan motor had 2 wires and an earth with a run capacitor in parallel across the supply wires.There was no diagram on the unit.I was pretty pushed for time so I didn't trace it out.Swapping the two supply wires had the desired effect.Condenser fan now runs the right way when the compressor is running but reverses when compressor cycles off.

Temprite
08-12-2004, 10:43 AM
I must of been in a hurry yesterday.I was fixing a gas leak on a coolroom at the same place and had another look at the case.Fan motor actually had 3 wires and earth,it wasn't a shaded pole as I first thought

coolkev
08-12-2004, 01:00 PM
:cool: Orford? the early ones run forward on ref and reversed on off cycle. Later models have a timer for off cycle so they only run for part of off cycle as they had alot of noise complaints on early models. They sell a kit to convert the early ones.