Reversible dual voltage motors with thermal protectors get
complicated, at least to me.听 But capacitor motors tend not to be
terrifically fussy about the value of the capacitor.听 Most
fractional hp motors will start with a cap of a couple of hundred mFD,
though the starting torque will be influenced.听听 The voltage
the cap sees will vary with the design of the motor and isn't necessarily
related to the supply voltage.
I always feel it should be said that motors with auto reset thermal
protectors (common on furnace blower motors, etc) should NOT be used on
power tools unless the protector is jumpered or replaced with a manual
type (typically with a red button).
am
At 06:15 PM 4/20/2020 +0000, you wrote:
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Robert Wrote
� I抣l mention that if
the motor is a dual-voltage one (120/240 VAC), there is usually still
only one start winding and if the motor is wired up to run off of 240
VAC, the start winding is still running off of 120 VAC (it will be wired
line to neutral).听 So the start capacitor range will be the same as
shown on the chart for 120 VAC, not 240 VAC. �
听
This isn抰 really the case.听 When
operating a Dual rated 120/240 (or 120/208 (in case of a wye source,
rather than a typical split phase) there is NO neutral run to the motor,
just the two 揾ots� and a ground.听 Attached (Hopefully) are relevant
NEMA MG-1 standard terminal markings and wiring for a number of different
configurations. Single voltage, dual voltage, Single and dual caps, and
Reversible. Mind you cheap import motors may, or may not,听 follow
nema standards.
听
听
听
听
听
R James
(Jim) Klessig P.E. | Senior Power Systems Engineer |
Electrical Reliability Services, VERTIV
jim.klessig@...
,
jim_klessig@...
1876 Gwin Rd, Mckinleyville | CA | 95519 | USA
| Cell (707) 497-9611 | eFax
614-410-0653
听
听
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