Standards that apply to Machines Driven
By 120 and 240 Volt Motors:
(U.S. Occupational Safety and Health
Administration 29 CFR #1910.213. (b) (3)*)
"On applications where injury to the operator might result if motors were to restart after a power failure, provisions shall be made to prevent machines from automatically restarting upon restoration of power."
*Electrical Controls for Wood Working Machinery "
*Electrical Controls for Wood Working Machinery
for Industrial Machinery,
"7.5.3 Restarting. "7.5.3 Restarting. Upon restoration of the voltage or upon switching on the incoming supply, automatic or unintentional restarting of the machine shall be prevented when
such a restart causes a hazardous condition."
And Annex A:
”A.3.3.103 Undervoltage Protection. The principal objective of this device is to
prevent automatic restarting of the equipment.“
(NFPA 70: National Electrical Code, International Electrical Code Series)
430.43 Automatic Restarting. . . . A motor overload device that can restart a motor automatically after overload tripping shall not be installed if automatic restarting of the motor can result in injury to persons.
|CSA C22. 1-98
Undervoltage protection required for motors:
”When automatic restarting is liable to create a hazard, the motor control device shall provide low-voltage protection.”
(Canadian Electrical Code, Part 1, 28-312)
Automatic restart after overload:
”Where automatic restarting of a motor after a shutdown on overload
could cause injury to persons, the overload or overheating devices protecting the motor shall be arranged so that automatic restarting
"Where automatic restarting of a motor after a shutdown on overload could cause injury to persons, the overload or overheating devices protecting the motor shall be arranged so that automatic restarting cannot occur."