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nfpa-70_430_motors.md
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@@ -6,7 +6,7 @@ tags:
- authorship/other
- destiny/uncertain
- exclude-from-word-count
- status/incomplete
- status/draft
- topic/construction/electrical
- type/media
title: Article 430 Motors, Motor Circuits, and Controllers
@@ -294,7 +294,7 @@ Enclosures for motor controllers and disconnecting means shall not be used as ju
Minimum wire-bending space within the enclosures for motor controllers shall be in accordance with Table 430.10(B) where measured in a straight line from the end of the lug or wire connector (in the direction the wire leaves the terminal) to the wall or barrier. Where alternate wire termination means are substituted for that supplied by the manufacturer of the controller, they shall be of a type identified by the manufacturer for use with the controller and shall not reduce the minimum wire-bending space.
Table 430.10(B) Minimum Wire-Bending Space at the Terminals of Enclosed Motor Controllers
##### Table 430.10(B) Minimum Wire-Bending Space at the Terminals of Enclosed Motor Controllers
Size of Wire (AWG or kcmil) Wires per Terminal
1 2
@@ -387,7 +387,7 @@ Where these terminal housings enclose rigidly mounted motor terminals, the termi
| 250 or less | 6 mm (1⁄4 in.) | 6 mm (1⁄4 in.) |
| Over 250 – 1000 | 10 mm (3⁄8 in.) | 10 mm (3⁄8 in.) |
Table 430.12(C)(2) Usable Volumes — Fixed Terminals
#### Table 430.12(C)(2) Usable Volumes — Fixed Terminals
| Power-Supply Conductor Size (AWG) | Minimum Usable Volume per Power-Supply Conductor |
| --------------------------------- | ------------------------------------------------ |
@@ -510,7 +510,7 @@ For a part-winding connected motor, the ampacity of the branch-circuit conductor
Conductors for a motor used in a short-time, intermittent, periodic, or varying duty application shall have an ampacity of not less than the percentage of the motor nameplate current rating shown in Table 430.22(E), unless the authority having jurisdiction grants special permission for conductors of lower ampacity.
Table 430.22(E) Duty-Cycle Service
##### Table 430.22(E) Duty-Cycle Service
Classification of Service
@@ -597,7 +597,7 @@ For other than continuous duty, these conductors shall have an ampacity, in perc
Where the secondary resistor is separate from the controller, the ampacity of the conductors between controller and resistor shall not be less than that shown in Table 430.23(C).
Table 430.23(C) Secondary Conductor
##### Table 430.23(C) Secondary Conductor
| Resistor Duty Classification | Ampacity of Conductor in Percent of Full-Load Secondary Current |
|:---------------------------- | ---------------------------------------------------------------:|
@@ -864,7 +864,7 @@ Where fuses are used for motor overload protection, a fuse shall be inserted in
Where devices other than fuses are used for motor overload protection, Table 430.37 shall govern the minimum allowable number and location of overload units such as trip coils or relays.
Table 430.37 Overload Units
#### Table 430.37 Overload Units
Kind of
@@ -966,7 +966,7 @@ The motor branch-circuit short-circuit and ground-fault protective device shall
A protective device that has a rating or setting not exceeding the value calculated according to the values given in Table 430.52 shall be used.
Table 430.52 Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault
##### Table 430.52 Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault
Protective Devices
@@ -1254,15 +1254,13 @@ The overcurrent protection for conductors shall be provided as specified in 430.
##### 430.72(B)(1) Separate Overcurrent Protection.
Where the motor branch-circuit short-circuit and ground-fault protective device does not provide protection in accordance with
430.72(B)(2), separate overcurrent protection shall be provided. The overcurrent protection shall not exceed the values specified in
Column A of Table 430.72(B).
430.72(B)(2), separate overcurrent protection shall be provided. The overcurrent protection shall not exceed the values specified in Column A of Table 430.72(B).
##### 430.72(B)(2) Branch-Circuit Overcurrent Protective Device.
Conductors shall be permitted to be protected by the motor branch-circuit short-circuit and ground-fault protective device and shall require only short-circuit and ground-fault protection. Where the conductors do not extend beyond the motor control equipment enclosure, the rating of the protective device(s) shall not exceed the value specified in Column B of Table 430.72(B). Where the conductors extend beyond the motor control equipment enclosure, the rating of the protective device(s) shall not exceed the value specified in Column C of Table 430.72(B).
Table 430.72(B) Maximum Rating of Overcurrent Protective Device in Amperes
##### Table 430.72(B) Maximum Rating of Overcurrent Protective Device in Amperes
Column A
@@ -1513,7 +1511,7 @@ One pole of the controller shall be permitted to be placed in a permanently grou
Each motor shall be provided with an individual controller.
> [!important] Exception No. 1:
> [!important] Exception No. 1: ^87-ex1
> For motors rated 1000 volts or less, a single controller rated at not less than the equivalent horsepower, as determined in accordance with 430.110(C)(1), of all the motors in the group shall be permitted to serve the group under any of the following conditions:
* (1) Where a number of motors drive several parts of a single machine or piece of apparatus, such as metal and woodworking machines, cranes, hoists, and similar apparatus
@@ -1522,7 +1520,7 @@ Each motor shall be provided with an individual controller.
* (3) Where a group of motors is located in a single room within sight from the controller location
> [!important] Exception No. 2:
> [!important] Exception No. 2: ^87-ex1
> A branch-circuit disconnecting means serving as the controller as allowed in 430.81(A) shall be permitted to serve more than one motor.
### 430.88 Adjustable-Speed Motors.
@@ -1606,11 +1604,7 @@ The minimum wire-bending space at the motor control center terminals and minimum
Spacings between motor control center bus terminals and other bare metal parts shall not be less than specified in Table 430.97(D).
#### 430.97(E) Barriers.
Barriers shall be placed in all service-entrance motor control centers to isolate service busbars and terminals from the remainder of the motor control center.
Table 430.97(D) Minimum Spacing Between Bare Metal Parts
##### Table 430.97(D) Minimum Spacing Between Bare Metal Parts
Nominal
@@ -1635,6 +1629,10 @@ Not over 250 volts, nominal
Not over 600 volts, nominal
50.8 2 25.4 1 25.4 1
#### 430.97(E) Barriers.
Barriers shall be placed in all service-entrance motor control centers to isolate service busbars and terminals from the remainder of the motor control center.
### 430.98 Marking.
#### 430.98(A) Motor Control Centers.
@@ -1817,8 +1815,7 @@ Where two or more motors are used together or where one or more motors are used
The rating of the disconnecting means shall be determined from the sum of all currents, including resistance loads, at the full-load condition and also at the locked-rotor condition. The combined full-load current and the combined locked-rotor current so obtained shall be considered as a single motor for the purpose of this requirement as follows.
The full-load current equivalent to the horsepower rating of each motor shall be selected from Table 430.247, Table 430.248, Table
430.249, or Table 430.250. These full-load currents shall be added to the rating in amperes of other loads to obtain an equivalent fullload current for the combined load.
The full-load current equivalent to the horsepower rating of each motor shall be selected from Table 430.247, Table 430.248, Table 430.249, or Table 430.250. These full-load currents shall be added to the rating in amperes of other loads to obtain an equivalent full-load current for the combined load.
The locked-rotor current equivalent to the horsepower rating of each motor shall be selected from Table 430.251(A) or Table
430.251(B). The locked-rotor currents shall be added to the rating in amperes of other loads to obtain an equivalent locked-rotor current for the combined load. Where two or more motors or other loads cannot be started simultaneously, the largest sum of locked-rotor currents of a motor or group of motors that can be started simultaneously and the full-load currents of other concurrent loads shall be permitted to be used to determine the equivalent locked-rotor current for the simultaneous combined loads. In cases where different current ratings are obtained when applying these tables, the largest value obtained shall be used.
@@ -1865,15 +1862,11 @@ An oil switch used on a circuit whose rating does not exceed 1000 volts or 100 a
Each motor shall be provided with an individual disconnecting means.
> [!important] Exception:
> A single disconnecting means shall be permitted to serve a group of motors under any one of the conditions of (1), (2), and
(3). The single disconnecting means shall be rated in accordance with 430.110(C).
* (1) Where a number of motors drive several parts of a single machine or piece of apparatus, such as metal- and woodworking machines, cranes, and hoists.
* (2) Where a group of motors is under the protection of one set of branch-circuit protective devices as permitted by 430.53(A).
* (3) Where a group of motors is in a single room within sight from the location of the disconnecting means.
> [!important] Exception: ^112-ex
> A single disconnecting means shall be permitted to serve a group of motors under any one of the conditions of (1), (2), and (3). The single disconnecting means shall be rated in accordance with 430.110(C).
> * (1) Where a number of motors drive several parts of a single machine or piece of apparatus, such as metal- and woodworking machines, cranes, and hoists.
> * (2) Where a group of motors is under the protection of one set of branch-circuit protective devices as permitted by 430.53(A).
> * (3) Where a group of motors is in a single room within sight from the location of the disconnecting means.
### 430.113 Energy from More Than One Source.
@@ -1957,10 +1950,10 @@ Adjustable-speed drive systems shall protect against motor overtemperature condi
* (2) Adjustable-speed drive system with load and speed-sensitive overload protection and thermal memory retention upon shutdown or power loss
Exception to (2): Thermal memory retention upon shutdown or power loss is not required for continuous duty loads.
> [!important] Exception to (2):
> Thermal memory retention upon shutdown or power loss is not required for continuous duty loads.
* (3) Overtemperature protection relay utilizing thermal sensors embedded in the motor and meeting the requirements of 430.126(A)
(2)
* (3) Overtemperature protection relay utilizing thermal sensors embedded in the motor and meeting the requirements of 430.126(A)(2)
* (4) Thermal sensor embedded in the motor whose communications are received and acted upon by an adjustable-speed drive system
@@ -1983,9 +1976,8 @@ For multiple motor applications, individual motor overtemperature protection sha
### 430.128 Disconnecting Means.
The disconnecting means shall be permitted to be in the incoming line to the conversion equipment and shall have a rating not less than 115 percent of the rated input current of the conversion unit.
430.130 Branch-Circuit Short-Circuit and Ground-Fault Protection for Single Motor Circuits Containing
Power Conversion Equipment.
### 430.130 Branch-Circuit Short-Circuit and Ground-Fault Protection for Single Motor Circuits Containing Power Conversion Equipment.
#### 430.130(A) Circuits Containing Power Conversion Equipment.
@@ -1993,9 +1985,7 @@ Circuits containing power conversion equipment shall be protected by a branch ci
* (1) The rating and type of protection shall be determined by 430.52(C)(1), (C)(3), (C)(5), or (C)(6), using the full-load current rating of the motor load as determined by 430.6(A) or (B).
Exception to 1: The rating and type of protection shall be permitted to be determined by Table 430.52 using the power conversion equipment’s rated input current where the power conversion equipment is listed and marked “Suitable for Output
Motor Conductor Protection.”
Exception to 1: The rating and type of protection shall be permitted to be determined by Table 430.52 using the power conversion equipment’s rated input current where the power conversion equipment is listed and marked “Suitable for Output Motor Conductor Protection.”
> [!info] Informational Note No. 1:
> Motor conductor branch circuit short-circuit and ground-fault protection from the power conversion equipment to the motor is provided by power conversion equipment that is listed and marked “Suitable for Output Motor
@@ -2096,7 +2086,7 @@ The ultimate trip current of overcurrent (overload) relays or other motor-protec
### 430.227 Disconnecting Means.
The controller disconnecting means shall be lockable in accordance with 110.25.
The controller disconnecting means shall be lockable in accordance with [[nfpa-70_110_requirements#110.25 Lockable Disconnecting Means.|110.25]].
## Part XII. Protection of Live Parts — All Voltages
@@ -2190,7 +2180,7 @@ Instrument transformer secondaries and exposed non–current-carrying metal or o
## Part XIV. Tables
Table 430.247 Full-Load Current in Amperes, Direct-Current Motors
### Table 430.247 Full-Load Current in Amperes, Direct-Current Motors ^t247
The following values of full-load currents* are for motors running at base speed.
@@ -2223,9 +2213,7 @@ Armature Voltage Rating*
200 — — — 675 330 294
*These are average dc quantities.
Table 430.248 Full-Load Currents in
Amperes, Single-Phase AlternatingCurrent Motors
### Table 430.248 Full-Load Currents in Amperes, Single-Phase Alternating-Current Motors ^t248
The following values of full-load currents are for motors running at usual speeds and motors with normal torque characteristics. The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of 110 to 120 and 220 to 240 volts.
@@ -2255,9 +2243,7 @@ Volts
71⁄2 80 46.0 44.0 40
10 100 57.5 55.0 50
Table 430.249 Full-Load Current, Two-Phase
Alternating-Current Motors (4-Wire)
### Table 430.249 Full-Load Current, Two-Phase Alternating-Current Motors (4-Wire) ^t249
The following values of full-load current are for motors running at speeds usual for belted motors and motors with normal torque characteristics. Current in the common conductor of a 2-phase, 3-wire system will be
1.41 times the value given. The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of
@@ -2327,7 +2313,7 @@ Volts
150 — 312 156 125 32
200 — 416 208 167 43
Table 430.250 Full-Load Current, Three-Phase Alternating-Current Motors
### Table 430.250 Full-Load Current, Three-Phase Alternating-Current Motors ^t250
The following values of full-load currents are typical for motors running at speeds usual for belted motors torque characteristics. The voltages listed are rated motor voltages. The currents listed shall be permitted ranges of 110 to 120, 220 to 240, 440 to 480, and 550 to 600 volts.
@@ -2358,16 +2344,7 @@ Facto
75 — 221 211 192 96 77 20 155 78
*For 90 and 80 percent power factor, the figures shall be multiplied by 1.1 and 1.25, respectively.
Table 430.251(A) Conversion Table of SinglePhase
Locked-Rotor Currents for Selection of
Disconnecting Means and Controllers as
Determined from Horsepower and Voltage Rating
For use only with 430.110, 440.12, 440.41, and
455.8(C).
### Table 430.251(A) Conversion Table of Single-Phase Locked-Rotor Currents for Selection of Disconnecting Means and Controllers as Determined from Horsepower and Voltage Rating For use only with 430.110, 440.12, 440.41, and 455.8(C). ^t251a
Rated
@@ -2387,11 +2364,7 @@ Amperes, Single Phase
7½ 480 265 240
10 1000 332 300
Table 430.251(B) Conversion Table of Polyphase Design B, C, and D Maximum Locked-Rotor Currents for
Selection of Disconnecting Means and Controllers as Determined from Horsepower and Voltage Rating and Design Letter
For use only with 430.110, 440.12, 440.41, and 455.8(C).
### Table 430.251(B) Conversion Table of Polyphase Design B, C, and D Maximum Locked-Rotor Currents for Selection of Disconnecting Means and Controllers as Determined from Horsepower and Voltage Rating and Design Letter For use only with 430.110, 440.12, 440.41, and 455.8(C). ^t251b
Rated