Motor calculations
A circuit breaker suitable for use as a. Motor disconnecting means must have a current rating of at least
115% of the motor full load current
Dual- element, time delay fuses may be sized up to
175% of the motors full load next standard breaker size
Three phase motor with four stator poles has a synchronous speed of
1800 rpm
If the current drawn by a three phase motor operating at 480 volts is 10.2 ampere what will the current most likely be if the motor is reconnected to run and is operated at 240 volts with all conditions being the same
20.4 amperes the amps double with
15 to 18 motor leads
2400b three phase motor
Non time delay fuses can be sized at
300% find next standard breaker size
The most common number of leads found on a three phase wye round motor is
9
Mscps are designed for use in
A special type of fusible switch combination motor starter
Stator windings can be described as
A structure of copper or aluminum wire coils
A synchronous motor is a type
AC motor
A dual voltage motor, delta connected motor always has nine leads
False it can have 12 leads
The main purpose of motor overload protection is to protect the motor
From damaging overload currents
Time delay delays do not
Provide over current protection
Nec section ______ requires that the ampaxity of branch circuit conductors supply a single continuous duty motor must not be less than 125% of the full load current rating.
Section 430.22(A)
Two or more motors of any rating each with its own overload protection can be connected to one branch circuit if
They have individual short circuit protection devices w
The most common three phase motor configuration are
Wye and delta