Specifications

Single-Phase Power From a 3-Phase Line
Question: Can I operate a power product that requires 220vac single-phase, from a 208vac 3-phase power line?
Answer: The figure below shows how you can draw close to the required voltage from a 3-phase power line. This
will work satisfactorily when the power line is reasonably close to nominal value. However, it is possible that the
power product may not be able to produce full power when the 208 Vac line is at the low end of its tolerance. For
example if the 208 Vac line were –10%, the resultant input voltage would be 187 Vac. This is below the minimum
acceptable voltage for the power product, which would be 191 Vac for a 220 Vac input line setting.
A
B
C
phase
phase
phase
NL
Rear of Instrument
Note: Connections are made from
line to line.
Earth
(Safety Ground)
120 Volts (typ)
208 Volts (typ)
Assume V(nominal) = 208 Vac
208 V @ 8% low = 191 V
208 V @ 12% high = 233 V
(Instrument operates between 191 & 250 Vac)
instrument will not operate on a 120 Vac line
Instrument requires an a.c.input voltage
in the window 191 - 250 Vac