Graph determines effect of stalled motor on a distribution system and eliminates hand calculation of amperage in emergencies. Graph is useful to any manufacturer, contractor, or maintenance department involved in electrical technology

Peck, R. R.

English

NASA Technical Reports Server

1972
B72-10075 
•	 NASA TECH BRIEF 
Manned Spacecraft Center
	 W 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Offi ce, NASA, Code KT, Washington, D.C. 20546. 
Graph for Locked Rotor Current 
GRAPH BASED ON: 
NATIONAL ELECTRICAL CODE 430-7 
AND 3 PHASE FORMULA 
- KVA/HPXHPXICOO 
- PHASE TO PHASE VOLT Xt/S 
I PHASE FORMULA 
- KVA/HPXHPXI000 
- PHASE TO NEUTRAL VOLT 
30 
208V
30 
Es
	 I 240V
30 
480 V 
IN 
MOTOR CODE 
LOCKED ROTOR CURRENT 
EXAMPLE: 10 HORSEPOWER MOTOR, 
CODED "E" -
 3 PHASE - 480 VOLTS, 
-APPR 600 AMPS
30 
2400V
1000 
4160 V
	 AMP 
120V 
10
IIJ 
Electrical personnel in the, field can now quickly 
determine the effect of a stalled motor (locked rotor) 
on a distribution system by means of a graph. A copy
of this graph with an illustrative example of its use is 
shown. It eliminates hand calculation of amperage in 
an emergency and should prove useful to any manu-
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United 'States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19720000075 2020-03-17T03:24:17+00:00Z
facturer, contractor or maintenance department in-
volved in electrical technology. 
Note:
This Tech Brief is complete in itself. No additional 
information is available.
ratent status: 
No patent action is contemplated by NASA. 
Source: Roy R. Peck
North American Rockwell Corporation 
under contract to 
Manned Spacecraft Center
(MSC-15703) 
Category 06


Graph for locked rotor current

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