ML19263F432

Responds to NRC Dec 1979 Request for Info Re Safeguard Motor Voltage Ratings.Safeguard Motors Rated to Start & Accelerate Loads w/80% Voltage.Motors Can Carry Normal Loads at 80% W/O Overheating

ML19263F432
Person / Time
Site:	Point Beach
Issue date:	01/17/1980
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton, Schwencer A Office of Nuclear Reactor Regulation
References
TAC-47404, TAC-47405, NUDOCS 8001280340
Download: ML19263F432 (2)

Text

.e-8 wisconsin Electnc m coum 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI S3201 Tanuary 17, 1980 Mr. Harold R.

Denton, Director Office of Nuclear Reactor Regulation U.

S. NUCLEAR REGULATORY COMMISSION Washington, D.

C.

20555 Attention:

Mr.

A.

Schwencer, Chief

~

Operating Reactors Branch 1 Gentlemen:

DOCKET NOS. 50-266 AND 50-301 ADDITIONAL INFORMATION DEGRADED AUXILIARY BUS VOLTAGE POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 In response to the NRC's request for additional infor-mation dated July 3, 1979, we provided a modification to our Technical Specification Change Request No. 45 by letter dated August 24, 1979.

This information included a discussion of voltage monitors on the plant auxiliary buses.

In December, Mr. Trammell of your Staff called to discuss the topic of voltage monitors further.

During this discussion, Mr. Trammell requested that we provide information on the safeguards motor voltage ratings and the results of our tests to determine minimum pickup and maximum dropout voltages for the safeguards motor starters.

The safeguards motors are rated to start and accelerate their loads with 80% voltage.

They are rated to run continuously at 90% to 110% voltage.

However, since the motors have a service factor of 1.15 and are not loaded beyond 1.0, they can carry their normal loads at 80% voltage without overheating.

The 480 volt motor starter pickup and dropout tests demonstrated that the size 1 and 1R contactors would pick up at 87 volts (72.5% of nominal) and would drop out at 62 volts (51.7%

of nominal).

The size 2 and 4 contactors picked up at 85 volts (70.8% of nominal) and dropped out at 60 and 63 volts respectively (50% and 52.5% of nominal).

There are no size 3 safeguards motor starters.

/40/S 1816 301 5

i/O 800128o 3 4 O

,,g-Mr. Harold R.

Denton January 17, 1980 We trust this information satisfies the questions expressed in your call.

Please advise us if you require any further information.

Very truly yours, k

da C.

W.

Fa irector Nuclear Power Department 1816.302