
875DP/500DP/500HV DUAL PULSE
RESISTANCE WELDING POWER SUPPLIES
990-290
2-1
CHAPTER 2
INSTALLATION
Location
Install the power supply in a well-ventilated area that is free from dirt and moisture. Allow sufficient
clearance around the sides and rear of the unit so that cooling air may flow properly. Position the power
supply as close as practical to the weld head.
Power Line
CAUTION:
Do not connect the line cord at this time.
This power supply was wired for the specific input line voltage marked on the line cord at the factory. The
standard unit is wired for 115 VAC. Reconnection for operation at another voltage may be made by a
qualified technician. Refer to Chapter 7 under
Modifications and Calibration.
Welding Cables
Position the power supply on the work bench approximately 5 inches behind the weld head. Use the cables
furnished with the weld head to connect the terminals on the back of the weld head to the appropriate
terminals on the front of the output transformer. Convention is to connect the lower electrode of the weld
head or hand-piece to the (+) output terminal and the upper electrode to the ( - ) output terminal of the
power supply. If the weld head cables are unserviceable, use the following criteria in selecting new cables:
x
Use No. 2 AWG welding cables, or No. 2/0 AWG welding cables if the cables are more than 12 inches
long. The diameter of the cables should be as large as practical.
x
Use the shortest possible welding cables. It is not uncommon to have losses up to 50% per foot for No.
6 cable and 20% for No. 2 cable.
To reduce energy losses, follow these recommendations:
x
Route cables so that they do not surround magnetic materials such as air solenoids, tooling, or steel weld
heads (see figure 2-1).