Emerson SZV22 用户手册

All shutdown devices are dry contact switches rated Class I, Division II that are wired to a terminal box 
for connection to the packager supplied control circuit. The common wires on all switches are connected 
together. All switches are closed unless a fault condition is detected.

All safety and protective devices must be installed and used in accordance with applicable codes and 
regulations.

All switch connections are wired to terminal strips in a junction box on the Compressor Module.

•  Low Inlet Gas Pressure

Normally Open, closes on pressure rise

•  High Discharge Gas Pressure

Normally Closed, opens on pressure rise

•  High Temperature

Normally Closed, opens on temperature rise

•  Compressor power for a variable speed Compressor Module is the Variable Frequency Drive (VFD).

•  Compressor speed control can be either a 4-20 mA or 0-10V signal (transducer supplied by customer) 

applied to the VFD. Speed can also be manually controlled with a potentiometer or the VFD can be 
set for a fi xed speed.

•  The Compressor is protected by the VFD.

•  The customer control circuit must supply an Enable signal to the VFD before the drive will accept a 

Run Fwd signal.

•  The VFD will start when the Enable signal is on and a Run Fwd signal is applied.

•  The VFD will stop if the Run Fwd signal is off or the Enable signal is removed.