Motors - hdbk10920122

DOE-HDBK-1092-98

5. The disconnect shall not be provided with a means of being operated from a remote location.

6. A circuit breaker disconnecting means shall not be opened automatically by a fire alarm

system, except as allowed by NEC Section 620-51(b).

7. The within-sight rule applies to all elevator equipment disconnects. Specific locations are

given for elevators with or without field control.

8. The disconnecting means shall be installed in a location that is readily accessible to only

qualified persons.

When power from more than one source is used for single- or multiple-car installations, a separate

disconnect should be provided for each source. These disconnects should be in sight of the equipment

supplied, and warning signs should be placed on or adjacent to the disconnect to read. For example,

"Warning: Parts of the control panel are not deenergized by this switch."

Lighting circuits for each elevator require a disconnect switch in the equipment room labeled for the

car it serves and lockable in the open position.

6.3.2.4 MOTORS

Elevator and escalator motors are considered as intermittent duty. This allows them to be protected

by the overcurrent protection device supplying the power for the branch circuit, which is selected by

the percentages in NEC Table 430-22(a) times the full load current of the motors. For example: What

is the load for a 15-minute rated 40-hp, 460-V, three-phase motor used as a freight elevator motor?

Step 1:

Finding full load current--NEC

Table 430-150

40 HP = 52 A

Step 2:

Finding demand factors--

NEC Table 430-22(a)

15 minute rated = 85%

Step 3:

Calculating load

52 A x 85% = 44.2 A

Answer: Load is 44.2 amps.

6.3.2.5 GROUNDING

All metal raceways and cables, Types MC, MI, or AC, shall be bonded to the metal frame of the car.

All elevator equipment including metal enclosures for electric devices on the car shall be grounded

in accordance with NEC Article 250.

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