Reducing Startup Current

[mini-split-dude]

Hi,

I need to run 3 split air conditioners on a 7.5Kva max genset, the y will be around 9000btu and will have an running consumption of around 4.3A@230v but with a starting current of 4x times, any ideas on how to reduce this.

Thanks for your help.

[coolguysfl]

A X V = W

4.3 A X 230 V = 989 Watts (full load according to the specs you provided)

Yes it is true Locked Rotor (starting amps will be 3-5 times the full load) so here's a couple of thoughts:

1) Get a generator capable of handling the "in rush" load.
2) Get a professional to build an interlock to prevent them all from starting at at the same time.
3) Get a professional to evaluate the application of a pump down systems to reduce starting torque required.
4) Get a professional to evaluate start assist components.

Other that #1 - you need a professional.

Note w/ generator usage -- use ONLY in well ventilated areas, DO NOT omit factory ground connections.

[allan38]

Originally posted by mini-split-dude
Hi,

I need to run 3 split air conditioners on a 7.5Kva max genset, the y will be around 9000btu and will have an running consumption of around 4.3A@230v but with a starting current of 4x times, any ideas on how to reduce this.

Thanks for your help.


operating power 989 watts each
total op power = 2967 watts

startup power = 3956 watts each.
Put a delay on make delay on number 2 and 3. Time the delay on make at 2 and 4 minutes.
put a delay on make time delay in series with the delay on break delay many of them have. Controls go in series, loads go in parallel.

The first one will start, 3956 watts surge drops to 989 watts. 2 minutes later the second will start 3956 watts + 989 watts surge = 4945 watts, then drops to 1978 watts. 2 minutes later the third one will start 3956 watts + 1978 watts = 5934 watts dropping to 2967 watts.

If you don't want the genset to start with the load for the 1st one then put a 2 min delay on make timer on it and shift the other 2 back another 2 minutes.

I havn't tried this so it may not work. It's worth what you paid for it. As the advice is free you get double your money back if it doesn't work.