Instruction manual

3.5.2 Connect the pump-motor electrical supply
Notes: Wiring instructions for the pump-motor are also shown on a label inside the terminal-box cover.
The following procedure will ensure that the pump will rotate in the correct direction if phase 1 of
your electrical supply corresponds to line L1 in Figures 5 to 8, phase 2 corresponds to line L2 and
phase 3 corresponds to line L3. However, we recommend that you check the direction of rotation of
the pump as described in Section 3.5.3. You must use the procedure in Section 3.5.3 to check the
direction of rotation if you do not know the phase order of your electrical supply.
Use the following procedure to connect the electrical supply to the pump motor. Connect your
electrical supply to the pump-motor through a suitable contactor which has an overload
protection facility. Use appropriately rated 4-core cable and a suitable cable-gland.
1. Connect the phase-wires of your electrical supply cable to the appropriate terminals inside
the terminal-box (refer to Section 3.5.1 and to Figures 5 to 8).
2. Connect the earth (ground) wire to the earth (ground) terminal inside the terminal-box.
3. Refit the cover to the pump-motor terminal-box.
3.5.3 Check the direction of pump rotation
1. Look at the pump-motor cooling-fan, switch on the DP180 for one or two seconds, then
switch the DP180 off again.
2. If the fan rotated anticlockwise when viewed from the motor end of the pump, the direction
of rotation is incorrect. If the direction of rotation is incorrect:
• Isolate the DP180 from the electrical supply.
• Remove the cover from the pump-motor terminal-box, reverse any two of the
phase-wires in the terminal-box, then refit the cover to the terminal-box.
•
Repeat the check from Step 1 to ensure that the direction of rotation is correct.
3.5.4 Connect the thermal snap-switch
The thermal snap-switch is fitted to the pump cooling-water jacket and is connected to the 2-way
terminal-block in the motor terminal-box.
You must use a suitable cable to connect the 2-way terminal-block to the motor-starter
overload-control loop, as shown in Figure 9.
You must connect the thermal snap-switch to the motor-starter overload-control loop so that, if
the DP180 overheats and the switch operates (that is, the switch contacts open), it will trip the
contactor and the DP180 will be switched off. When the pump cools and the switch contacts close
again, the DP180 will not then automatically restart; you must manually reset the contactor
before you can start the DP180 again.
12 DP180 Dry Vacuum Pump