Welch Vacuum 8925 Direct Drive Rotary Vane Pump - Manual (Page 16)

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4.04 Changing the Voltage Setting on 8905, 8920 and 8925 “A”- Models only
The vacuum pump motor is factory wired to for 115 V for models which operate at 60 Hz, and 230 V
for models which operate at 50 Hz. The motor wiring can easily be changed for operation at a voltage
different than that set at the factory. Models can be rewired to operate at either the low (115 V) or high
(220 V) voltage. Follow the motor wiring schematic located below, or on the motor shield. A line cord
plug suitable for 115 V connection (blades parallel) or 220 V connection (blades coplanar) is furnished
which complies with United States electrical codes. When changing the factory wiring, or when using
outside of the United States, replace the line cord plug with one suitable for the voltage connection
which meets the voltage to which the motor now is wired to require to operate.
4.05 Other Electrical Configurations
Other electrical configurations of Welch pumps may be available. Check with Welch for 3-Phase,
Explosion Proof and other motor configurations.
4.06 Explosion Proof Pumps (Explosion Proof Pumps must be ordered special)
Due to the added safety features of an explosion proof pump, the pump’s electrical supply must be
connected onsite by a trained electrician. Since there are numerous scenarios for connection, the
manufacturer does not provide guidelines or advice in electrical hookups. Of course we will assist in
choosing the correct explosion proof pump, but for safety reasons, we resist the temptation to advise
what cannot be seen.