Safety switch

From makernexuswiki
Jump to navigation Jump to search

A safety switch provides a way of disconnecting electrical power from a motor. The National Electrical Code (NEC) section 430.102B requires safety switches in the line of sight and within 50 feet of electric motors.

Most small motorized equipment have a built-in manually-operated power switch, which satisfies NEC requirements. Most of he mills at Maker Nexus have power switches which act as safety switches. The motors on some of the metal lathes are operated by motor controllers.

Motor controllers provide additional protections over simple manual switches. Motor controllers protect from single-phasing, where the power source no longer has all three phases. Motor controllers protect motors and equipment from phase reversal, which would cause the equipment to run backwards. Motor controllers provide many other forms of protection.

Unfortunately, motors controllers are complex and may cause motors to start without a command from the operator. For that reason, manual safety switches are also required by the NEC.

Some equipment at Maker Nexus lacks required safety switches. In that case the operator must pull the plug out of the receptacle to prevent unexpected starting, such as while changing the chuck on a lathe.

External links