Sound power limits for new large motors

[electricpete]

From reading the scope of NEMA MG-1 Part 9 we would conclude that it addresses motors up to 5000 hp:

“NEMA MG-1 2003
Section I GENERAL STANDARDS APPLYING TO ALL MACHINES
Part 9 ROTATING ELECTRICAL MACHINES—SOUND POWER LIMITS AND
MEASUREMENT PROCEDURES

SECTION 9.1 SCOPE
This Part specifies maximum no-load A-weighted sound power levels for factory acceptance testing of rotating electrical motors in accordance with this Standard and having the following characteristics:
a. motors with rated output from 0.5 HP through 5000 HP;
b. speed not greater than 3600 RPM;
c. 140 frame size and larger;
d. enclosures of the ODP, TEFC, or WPII type.”

However the associated tables 9-1 and 90-2 only address NEMA frame motors up to approx 500hp.

1 - Am I missing something in NEMA MG-1 which addresses sound requirements for large motors (as implied by the scope)? Or maybe it was a typo and 500 hp intended?

2 – What type of noise specification would you recommend for a new motor in an indoor machine-room environment – Power Plant Turbine Generator Building – hearing protection worn at all times.

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[jbartos]

Suggestion: Visit

http://www.reliance.com/mtr/pcno.htm

for Motor Noise issues. It can get involved if various regulations, e.g. OSHA, are to be complied with
Regarding NEMA MG-1 peculiarities, contact:

http://www.nema.org

for Errata, if any
and also, this topic may pose mechanical engineering challenges under Mechanical Engineers in this Forum

 

[aolalde]

Epete:

I do not have MG1-2003 version,
NEMA MG1-1998 rev 2- 2001, part 9.6, 9.7 and table 9-1 limits the maximum Overall Sound Power level Decibels, (ref 10^-12 watts):

For 5000 HP, 1801 to3600 rpm; 114 – ODP, 120-TEFC, 109-WPII
For 4000 HP, 1201 to1800 rpm; 110 – ODP, 115-TEFC, 106-WPII
For 3500 HP, 901 to1200 rpm; 109 – ODP, 111-TEFC, 105-WPII