OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

May 24, 1990

John Dugdale
Vice President
Sales and Marketing Saftronics, Inc.
5580 Enterprise Parkway
Fort Myers, Florida 33905

Dear Mr. Dugdale:

This is in response to your letter of April 20, concerning your company's Solid State Electronic AC Motor Brakes.

The braking device offered by your company appears to provide for dynamic braking of AC motors. As such, it should be a welcome device for use by various equipment manufacturers and users. Alternatively, various equipment is presently adapted with magnetic disk brakes to attain faster stopping of high inertia machines.

The Occupational Safety and Health Administration (OSHA) standards do not specifically mandate or require dynamic braking devices. However, the machine guarding standards of 29 CFR 1910, Subpart O, require that workers not be exposed to hazardous moving parts. In that regard, equipment manufactures and users modify many high inertia machines to assure the stopping of hazardous motion before an employee can become exposed (e.g., stopping a conveyor system after an interlocked barrier guard is triggered by an employee gaining access to the hazardous portion of the equipment.) A copy of the General Industry Standards, 29 CFR 1910, is forwarded under separate cover.

OSHA has no objection to the statement used in your brochure regarding the fact that your device would help meet OSHA safety standards for machine guarding. OSHA has no specific standards for motor stopping.

If we may be of further assistance, please contact us.


Patricia K. Clark Director
Designate Directorate of Compliance Programs