Chemglass AF-0349 Welch Vacuum Pump - Manual (Page 16)

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4.04 Changing the Voltage Setting on 8905, 8920 and 8925 “A”-Models
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 pump 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.