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W10MT3A Variac
INPUT POWER: Metered Variac Autotransformers are supplied with a three-wire cord
and plug for connection to 50-to 60-cycle nominal l20-volt power line. The third wire in
the cord-plug circuit provides automatic grounding of external metal parts, as a safety
feature. Do not attempt to operate the units on direct current, or damage will result.
LOADS: Metered Variac Autotransformers are suitable for the control of any alternating-
current load within their rating of 10 amperes Since they are connected for overvoltage
(117% of line) operation, care must be taken to avoid damage to loads that are incapable
of withstanding higher-than-line voltage. Metered models are, of course, particularly
useful in determining load current, or watts, versus applied voltage.
SWITCHING: To avoid possible destructive surges, set the control knob to the full
counter clockwise (zero voltage) position before connecting the autotransformer to
the line, or the load to the autotransformer. Slowly rotate the control knob clockwise
(increasing the voltage), and observe the meter. Unusually high readings signify trouble;
the voltage should be returned to zero and the trouble corrected. The meter range is
changed by a current transformer for highest possible accuracy; make-before-break
contacts permit switching under load.
ACCESS: No user-serviceable parts inside.
FUSE: The meter circuit of this unit are fused to prevent overload damage to the meter
movements. The fuse required is: 12 ampere Bussman Type ABC-12. These are fast-
blow types; replacement with slow blow fuses or fuses of a higher rating will endanger
the meters.
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Summary of Contents for W10MT3A
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