Wiring Pressure Switch

yes im using it strictly as a convertor, i have 1 phase power in my garage and im using the VFD to run my 3 phase compressor. i have it hooked up to my compressor motor and it works perfect , i can run the rpms any where i want to. i just need to know how to wire pressure switch to tiurn off and on. i know i dont know alot about this ,thats what i thought forum was for, to find answers. not to be called a dummy. ***hole

To run a standard 3~ 7.5 hp motor you need a 3~ supply with the correct voltage and a suitably sized magnetic starter and a suitably sized pressure switch. (single phase and often low voltage.) Why complicate life with a Variable Frequency Drive (VFD?) Or is it the Virginia Fire Dept? Besides, a VFD does NOT replace a mag. starter. And a word of friendly advice. One should use abbreviations with caution. To assume that everyone knows what the abbreviation means just "ain't so." As to the circuit itself, how do you expect anyone to send you a complete schematic in this forum. Talk to your friendly electro-mechanic. And another piece of friendly advice... if you don't know how to hook it up, stay away from it. Far away. ELECTRIC POWER IS LETHAL.

Assuming the VFD is suitable for this application, the information you need on both which inputs to use and the VFD settings necessary, are located in the VFD manual. The pressure switch will likely connect to one of the speed inputs (NOT the VFD's start/stop input) to control the air compressor.

If you don't have a copy then download one off the manufacturers website. Also look here for application information. Wiring diagrams should be included in the manual.

A pressure switch" is a discrete device; on or off. How is connecting that to a speed input going to work?

VFD's come with analog AND digital speed inputs. The digital speed inputs allow the drive to run at preset speeds just by closing an external contact or switch (such as tank level switches). Very handy for on-off process control (eg- maintaining a liquid or pressure level in a tank being filled and emptied at varying rates).

http://en.wikipedia.org/wiki/Control_system

if you want the pressure switch to start and stop the compressor then you will need to wire it to an input on the VFD and program the VFD to operate of the logic input. However normally a compressor will run continuously and the pressure switch will only control loading and unloding the compressor, in which case you should not be wiring it to the VFD it should be wired to the compressor control terminals.

You can use a Contactor with a VSD... thus wire all your Shutdowns to Deactivate the contactor...