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3 point relay control

thread248-18467

3 point relay control

3 point relay control

(OP)
Can anyone give me a brief overview of what 3 point relay control? I believe it may also be termed Hi / Lo control.

RE: 3 point relay control

can you tell us more about the application?
i am not sure if a "3 point control relay" is a universal term....could  be different in some textbooks

dydt

RE: 3 point relay control

(OP)
From what I can gather 3 point relay control or hi / lo control, is used as an alternative for temperature control e.g. for the control of an air damper against full PID modulating control.

RE: 3 point relay control

Sounds like you are going for 'digital control'.  

The max speed must be more than enough to satisfy the process.  Easiest way is to have one thermostat controlling the low speed function and a second TS bringing on the high speed winding if the motor low speed is insufficient (after a short time delay) to satisfy temperature.

Two stage control is a more common term, if the above describes your intent.

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