Powerex MTSD0503 - Control Operation

Scroll Medical & Laboratory Compressed Air Systems
Powerex • 150 Producon Drive • Harrison, OH 45030 • USA
P 1.888.769.7979 • F 513.367.3125 • www.powerexinc.com
IN907800AV • 08/2018
Page 7 of 40
Start Up and Operaon
1. Follow all procedures under “Before Start-Up” before
aempng operaon of the lab air system.
2. Make sure all selector switches are in the OFF posion.
3. Switch on electric source.
4. Open tank connecon valve or valves completely.
5. Using the selector switches on the control panel, turn on each
pump—motor in the “Auto” mode unl all are running.
6. Check for excessive vibraon, unusual noises or leaks during
operaon. If problems are detected, shut down the system
and make correcons or repair as needed before operang the
system.
7. Pumps may be operated in “hand” mode to override the
funcon of the automac controls. The pumps and the system
will not be damaged during “hand” mode operaon is used
for a short me. If hand mode if used for many hours, possible
overload and overheang may result along with more rapid
pump wear. The system safety valves may open if operated in
“hand” mode.
8. In normal operaon, leave all selector switches in the “Auto”
posion and allow the controls to cycle the pumps as needed
based on compressor demand.
Control Operaon
Systems are available with basic or premium controls. All controls
ulize a PLC to control the on o cycles of the pumps. The basic
controls have all the switches and indicator lights labeled. Operate
the system by turning the switches from OFF to AUTO unl all the
circuits are acve. Use the dryer selector to choose either dryer 1 or
dryer 2. During switchover temporarily use “BOTH”.
The system has a set of back-up pressure switches, if the pressure
gets low enough the backup low pressure switch will turn on all the
pumps. An alarm is triggered for “Reserve in Use” on medical systems
and “Low pressure” on lab systems. Similarly there is a high pressure
switch that will turn o the pumps even if the PLC fails to do so before
the system pressure rises beyond allowable levels. When the system
runs on the back up switches mulple motors may engage at the
same me generang high inrush amp draws.
A typical Medical system schemac with basic controls is shown on
page 8.
NOTE: In Medical and lab systems the Motor Protector Circuit
Breakers can be used to isolate a motor branch circuit to prevent the
motor from running. The fan motors and temperature switches are
not controlled by the MPCB (nor is the control signal to the motor
contactor) and must be depowered separately if needed.
If all pumps are running in the wrong direcon,
change the incoming power leads to correct
rotaon.
Premium Controls ulize a touch screen display to give and receive
informaon. This is oen referred to as a Human – Machine Interface
or HMI. The HMI screens and their funcons and capabilies are
discussed on page 14.