View Full Version : Time delay for multi compressors

05-11-2004, 11:06 PM

Need another opinion.

I'm in the process of installing some large split a/c systems to a building. Four of the systems are linked to one controller (looped together-one master and three slaves) These are 16 kW each. When the controller is activated, all the compressors are going to start at the same time, which I don't want to do, because each time they start up, the lights will dim.

I had thought about making a control system, mounted on a DIN rail linked into each of the compressors to give a time delay on the load side of the contactors, but noticed that there are some manufacturers-Eberle and Aspen who make time delay controls at a decent price.

I can't decide what to do. They are 3 phase systems 415VAC, so can anyone recommend a product to do the job for me please.

James :confused:

05-11-2004, 11:20 PM
Depending on the manufacturer some have a built-in time delay to provide load shedding on start up; check with them first.

You idea of a time delay on the load side of the contactor ?? Do you mean to interupt the 3 phases ?

Surely it would make more sense to to put them in the contactor coil circuit.....

You could fit ON DELAY timers to each contactor with different times on each one ?

Your move....

05-11-2004, 11:41 PM
Hi Brian,

I don't think there is a facility built in, and yes it would probably make more sense to place on the contactor coil-that was my other option once I have the coil voltage and amps etc.

06-11-2004, 12:03 AM
Try this: http://www.icmcontrols.com/ This seems to be a simple solution to tie into control contactor
ICM 105 | Ideal For Compressor Staging
Low holding current
Low cost version of the ICM102 without the cooling anticipator circuitry
Ideal for compressor staging
Universal voltage operation
Knob-adjustable time delays
Simple 2-wire hookup & up to 10 min adj timing

06-11-2004, 12:13 AM
Hi Guys,

Subject "Time delay on multiple compressors"

Anyone else come accross these stupid Norpe integral daries that use a light tube starter as a time delay to bring on the second compressor. I know these units are made cheap so they sell more by surely they can come up with something better than that :eek:



06-11-2004, 08:05 AM
Hi Iceman,
Looks like you've been busy. :)
A serial timer is the ultimate solution, simple and cheap.

I usually use the Supco TD 69, you can get it everywhere in the UK.

You only need a few seconds TD between the compressors.

Good luck.

Chemi :)