High data rate storage system B tape transport fits to existing hysteresis motor thus reducing flutter, lowering assembly cost, simplifying assembly process and increasing reliability. Motor may be used on any tape recorder or similar device having two speed ratio of up to 32 to 1

Clurman, S. P.

Stitley, G. L.

English

NASA Technical Reports Server

November 1971	 Brief 71-10409 
NASA TECH BRIEF
	
_4V Goddard Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield; Virginia 22151. Requests for individual copies or questions relating to the. Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D. f. 20546. 
Simple Two-Speed Tape Transport Drive 
The problem: 
Reduce the mechanical complexity of an existing 
two-speed tape transport drive; lower the assembly 
cost and increase the reliability. 
In the existing transport, a 32 to I ratio in play-
back-to-record tape speeds required a planetary 
drive system of belts, shafts and pulleys. Once-around 
frequencies in bearings, pulleys, and shafts, nutation 
frequencies in bearings, and dirt pickup all contrib-
uted to flutter and to the complexity of the 
assembly.
 
The solution: 
Fit an existing two-speed synchronous hysteresis 
motor to a High Data Rate Storage System (HDRSS) 
B tape transport. The flutter is reduced and the 
mechanical assembly greatly simplified. 
How it's done: 
The two-speed synchronous hysteresis motor uses 
a single frame and a single shaft. A speed of 375 
rpm is obtained by applying a 100 Hz driving vol-
tage to 32 poles; 12.000 rpm is reached by applying 
a 400 Hz voltage to 4 poles. 
The old and new drive systems were compared 
directly, using successive testing on the same tape 
transport with the original two-speed drive arrange-
ment. The two-speed motor was then mounted on 
the transport to replace the planetary drive sub-
assembly. A pulley was placed on the transport 
capstan so that a belt driven by the motor shaft 
would drive the capstan at tape speeds of 42.88 
in./sec for a 12,000 rpm motor speed and 1.34 
in./sec for a 375 rpm motor speed. This configura-
tion was then tested for 200 hours under the same 
conditions as for the original configuration. Play-
back flutter with the two-speed motor was 1.4%, 
compared to 3% with the old drive system. 
Through the use of the two-speed motor, three 
shafts, four belts, one brake, eleven bearings, and 
one motor were eliminated, materially reducing the 
mechanical complexity of the assembly, decreasing 
the cost, and increasing the reliability. If dynamic 
braking were to be incorporated, the remaining 
brake could be eliminated. 
Notes: 
I. This motor could be used on any tape recorder 
or similar device having a two-speed ratio of up 
to 32 to 1. 
2. The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: 
NASA CR-112400 (N70-36364), Nimbus-D 
High Data Rate Storage System 
Patent status: 
No patent action is contemplated by NASA. 
Source: S.P. Clurman and G.L. Stitley of

Astro- Electronics Div. 
Radio Corp. of America

under contract to

Goddard Space Flight Center

(G SC- 10981) 
Category 06 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19710000406 2020-03-17T02:29:57+00:00Z


Simple two-speed tape transport drive

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