What reason are there for connecting and disconnecting the solenoid valve once per e

[mori69]

Hi Dear Engineer s association

Please look at the figure No.1 which is attached .
This figure is about cntrolling screw compressor capacity.
There are four solenoid valves in this picture which one of them is connected to capillary tube which is called CR4 and as is mentioned at the catalog that this solenoid valve is had electricity once per 10 seconds .
now, I have a question (( What reason are there for connecting and disconnecting once per each 10 seconds ?))
Thank you

[james10]

Possibly oil return/motor cooling

[chilliwilly]

Yes definately for oil return to lube the screw meshings.

[RANGER1]

I think its more for slide valve creeping.
If at 33,66 or 100% load it pulses every 10 seconds to make sure its at that position.
Its got nothing to do with lubricating rotors.

[DTLarca]

I think its more for slide valve creeping.
If at 33,66 or 100% load it pulses every 10 seconds to make sure its at that position.
Its got nothing to do with lubricating rotors.

Indeed. This also allows the slide valve mechanism to continuously be in relative minute motion reducing the likely hood of seizing in position.

[Magoo]

As per Ranger1 said, pulse loading the capacity slide as required, saves massive loads on drive motor.

[mori69]

Thanks for your kind attention.

Any more comments are welcome.

[Paul J]

most compressor control circuts will pulse the solenoid to ensure it stays at that position, I haven't personabley seen it done at any position lower than 100% but it wouldn't hurt, if the teflon seal leaks a bit of oil past it, the compressor will slowly unload, so if the solenoid is pulsed it will maintain the same position