fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
I'm looking for constructive criticism on the following, and if you think it is merited, support in the form of comments from you on 12-19a. Thanks, Jim Williams
4 Comment:
620.13 Feeder and Branch-Circuit Conductors.
Conductors shall have an ampacity in accordance with 620.13(A) through (D). With generator field control, the conductor ampacity shall be based on the nameplate current rating of the driving motor of the motor-generator set that supplies power to the elevator motor.
Informational Note No. 1: The heating of conductors depends on root-mean-square current values, which, with generator field control, are reflected by the nameplate current rating of the motor-generator driving motor rather than by the rating of the elevator motor, which represents actual but short-time and intermittent full-load current values.
(A) Conductors Supplying Single Motor. Conductors supplying a single motor shall have an ampacity not less than the percentage of motor nameplate current determined from 430.22(A) and (E).
Informational Note: Some elevator motor currents, or those of similar functions, exceed the nameplate value, but because they are inherently intermittent duty and the heating of the motor and conductors is dependent on the root-mean-square (rms) current value, conductors are sized for duty cycle service as shown in Table 430.22(E). [ROP 12?19a]
(B) Conductors Supplying a Single Motor Controller. Conductors supplying a single motor controller shall have an ampacity not less than the motor controller nameplate current rating, plus all other connected loads. Motor controller nameplate current rating shall be permitted to be derived based on the rms value of the motor current using an intermittent duty cycle and other control system loads, if present. [ROP 12?19a]
__OR__
620.13 Feeder and Branch-Circuit Conductors.
Conductors shall have an ampacity in accordance with 620.13(A) through (D). With generator field control, the conductor ampacity shall be based on the nameplate current rating of the driving motor of the motor-generator set that supplies power to the elevator motor.
Informational Note No. 1: The heating of conductors depends on root-mean-square rms current values, which, with generator field control, are reflected by the nameplate current rating of the motor-generator driving motor rather than by the rating of the elevator motor, which represents actual but short-time and intermittent full-load current values.
(A) Conductors Supplying Single Motor. Conductors supplying a single motor shall have an ampacity not less than the percentage of motor nameplate current determined from 430.22(A) and (E).
Informational Note: Some elevator motor currents, or those of similar functions, exceed the nameplate value, but because they are inherently intermittent duty and the heating of the motor and conductors is dependent on the root-mean-square (rms) current value, conductors are sized for duty cycle service as shown in Table 430.22(E). [ROP 12?19a]
(B) Conductors Supplying a Single Motor Controller. Conductors supplying a single motor controller shall have an ampacity not less than the motor controller nameplate current rating, plus all other connected loads. Motor controller nameplate current rating shall be permitted to be derived based on the rms value of the motor current using an intermittent duty cycle and other control system loads, if present. [ROP 12?19a]
5 Statement of Problem and Substantiation.
'rms' is never referenced in the rest of the text in connection with current, only with voltage. 'rms' is not really related to duty cycle as suggested in (A).
__OR__
The dominate form of reference to root-mean-square is rms in the rest of the text.
4 Comment:
620.13 Feeder and Branch-Circuit Conductors.
Conductors shall have an ampacity in accordance with 620.13(A) through (D). With generator field control, the conductor ampacity shall be based on the nameplate current rating of the driving motor of the motor-generator set that supplies power to the elevator motor.
Informational Note No. 1: The heating of conductors depends on root-mean-square current values, which, with generator field control, are reflected by the nameplate current rating of the motor-generator driving motor rather than by the rating of the elevator motor, which represents actual but short-time and intermittent full-load current values.
(A) Conductors Supplying Single Motor. Conductors supplying a single motor shall have an ampacity not less than the percentage of motor nameplate current determined from 430.22(A) and (E).
Informational Note: Some elevator motor currents, or those of similar functions, exceed the nameplate value, but because they are inherently intermittent duty and the heating of the motor and conductors is dependent on the root-mean-square (rms) current value, conductors are sized for duty cycle service as shown in Table 430.22(E). [ROP 12?19a]
(B) Conductors Supplying a Single Motor Controller. Conductors supplying a single motor controller shall have an ampacity not less than the motor controller nameplate current rating, plus all other connected loads. Motor controller nameplate current rating shall be permitted to be derived based on the rms value of the motor current using an intermittent duty cycle and other control system loads, if present. [ROP 12?19a]
__OR__
620.13 Feeder and Branch-Circuit Conductors.
Conductors shall have an ampacity in accordance with 620.13(A) through (D). With generator field control, the conductor ampacity shall be based on the nameplate current rating of the driving motor of the motor-generator set that supplies power to the elevator motor.
Informational Note No. 1: The heating of conductors depends on root-mean-square rms current values, which, with generator field control, are reflected by the nameplate current rating of the motor-generator driving motor rather than by the rating of the elevator motor, which represents actual but short-time and intermittent full-load current values.
(A) Conductors Supplying Single Motor. Conductors supplying a single motor shall have an ampacity not less than the percentage of motor nameplate current determined from 430.22(A) and (E).
Informational Note: Some elevator motor currents, or those of similar functions, exceed the nameplate value, but because they are inherently intermittent duty and the heating of the motor and conductors is dependent on the root-mean-square (rms) current value, conductors are sized for duty cycle service as shown in Table 430.22(E). [ROP 12?19a]
(B) Conductors Supplying a Single Motor Controller. Conductors supplying a single motor controller shall have an ampacity not less than the motor controller nameplate current rating, plus all other connected loads. Motor controller nameplate current rating shall be permitted to be derived based on the rms value of the motor current using an intermittent duty cycle and other control system loads, if present. [ROP 12?19a]
5 Statement of Problem and Substantiation.
'rms' is never referenced in the rest of the text in connection with current, only with voltage. 'rms' is not really related to duty cycle as suggested in (A).
__OR__
The dominate form of reference to root-mean-square is rms in the rest of the text.