Randolph, A. G.

English

NASA Technical Reports Server

. .- 
1 I ,  
SYSTEM3 ENGINEERING LABORATORIES, INCORPORATED . 
P. 0. Box 9148 
For t  Lauderdale, Florida 33310 
9 November 1964 
SCO 2055-6980 
National Aeronautics and Space Administration 
George C. Marahall Space Flight Center 
Huntsvi&, Alabama 358 12 
Attention: Mr. H. RonaldGreene, PR-RC 
C o nt r act A dmini 8 t r a tor 
Contract NAS 8-1 1504 
Second Quarterly Report 
Sub j ec t : 
Gbntlernen: 
E 
This quarterly report of progress covers the reporting period ending I '  
17 October 1964. 
soon as they become available. 
Copica of engineering drawing6 will be forwarded as 
1.0 SUMMARY 
Al l  major items were  received this quarter with the exception 
converters manufactured by North Atlantic Industriee. These 
y8 been rescheduled twice this quarter due to non-delivery by 
North Atlantic. 
5 November 1964. 
The latest delivery estimate of these converters ie  
Two deoign review meeting8 were held thie quarter with MSFC 
representatives. 
rhielded patchcords instead of the single shielded conductor originally speci- 
fied. This will allow a greater number of channels to be brought in to the 
patchboards and a t  the same time reduce the number of patches required. 
patchcords have been ordered for this and are of the locking, twin detent, 
manual extraction type. 
It w a o  decided that the patchboards would use two conductor 
The 
The AC and DC mearuremente for the elay mu1 tiplexe r were 
split into two groups after relay evaluation showed this to-utfrclrtwt reliable 
method. I GPO PRICE $ 
I 
OTS PRICE(S) $ I 
I 
Hard copy (HC) / d l 0  ~ 
MicrnfichP IM FI 157 i 
https://ntrs.nasa.gov/search.jsp?R=19650003961 2020-03-17T00:49:44+00:00Z
NASA Huntsville 
Attn: M r ,  H. Ronald Greene -2 - 9 November 1964 
System design was eseentially completed this period with the 
exception of those parts dealing with the AC to DC converters and the limits 
to be set  on the alarm circuits. These limits a r e  to be supplied to the pro- 
ject a s  soon as defined by MSFC. 
Fabrication of printed circuit cards  i s  taking somewhat longer 
than anticipated dus to the use of MSFC standard 158B and 154. 
bo manufactured for spare parts will  therefore not be started until aystem 
cardo a re  complete. 
1 December 1964. 
Cards to 
Cards for the system should be completed by __ 
At the present time the project is still  slightly ahead of schedule 
and no delivery problems can be foreseen. 
2.0 TEST RESULTS 
Relay testing was Completed this period upith the following 
' reaulte: 
Relay Sample 1 
Manufacturer - Clare 
Type - DryReed 
Model Number - CR3Z 
This relay was evaluated to determine characteristics which 
would make it desirable for use in the system. 
at various rates with square wave drive. As the frequency was increased 
several resonance8 were noticed before reaching a ZOO eample per second 
rate. 
ueed and also to the fact that damping measures were ineufficient. 
t es t s  made on the relay indicate that it  is capable of withstanding voltages 
practigd limit due to manufacturers epecifications. 
istics of the relay a re  tabulated as follows: 
The relay was operated 
These resonances were due in part to the length of the armature 
Voltage 
4- ... d U ~ f e g &  =f 250 ~ o I ~ Q , .  This v ~ l t ~ , a ~ ,  hewever, w a g  c ~ ~ n i d c r e d  to bo the 
The basic test character- 
1. Operate Time 1 . 2  milliseconds nominal 
2. Bounce Time 200-500 microseconds 
3. Release Time 500 microseconds nominal 
4. Operating Rate < 100 samples per second 
5, Voltage Breakdown > 250 volts 
3 .  -7 t '  
). 
' *  
NASA Huntsville 
Attn: Mr. H. Ronald Greene - 3 -  9 November 1964 
Relay Sample 2 
It was decided to determine if a re lay could be produced with 
additional damping to provide greater operating speed. 
quested that the armature be shortened to relieve the resonances that occur 
due to the original length. 
It w a s  also re- 
After discussion with representives of Clare, a second relay WIS 
obtained which incorporated dimpling in  the glass bulb to restrain the arma- 
ture on i ts  releasing movement, 
noticed but 400 samples per second operation w a s  not feasible. 
A slight increase in operating speed wag 
Relay Sample 3 
Manufact-srer - Struthers-Dunn 
Type  - Dry Reed 
This relay was tested to provide information on a dry reed type 
relay with shorter armature than could be obtained from Clare. 
The results of testing indicated the following: 
1. Operate Time 1 . 0  milliseconds 
2, Bounce Time 350 microseconds nominal 
3. Release Time 150 microseconds nominal 
4. Operating Rate 150 samples per second maximum 
5. Voltage Breakdown 7 250 volts 
This relay w a s  faster than the Clare but again the operating speed 
did not approach the desired 400 samples per second. 
at the higher operating rates which Jhnited the relay in its operating capability. 
Resonances occurred 
Manufacturer - James 
T w e  - High Speed Micro-scan 
Model - C-4680 
This relay was thoroughly tested under various operating conditions 
and was additionally life tested. The relay contains a form-K contact arrange- 
ment which provides a center otable off condition and thus a break before make 
feature. This allows five channels to be placed on the same relay. 
The following tobls rtatsr the eeroential characteristics as determined 
from teats: 
I 
NASA Huntsville 
Attn: Mr .  H. Ronald Greene -4- 9 November 1964 
1. Operate Time 0.75 - 1 millisecond 
.2. Bounce Time Not notice able 
3. Release Time 350-500 microseconds 
4. Operating rate 0-600 samples per second 
5. Voltage Breakdown < 0 volte varies between contacts 
6. Life (Standard model) 200 ,000 ,000 operations 
7. Live Expectancy One Billion Operations - 
(Deluxe Model) 
1. 
The life test on the relay was run with various voltages applied 
at different times as might be found in actual operation. 
ranged from 1 to 60 volts normally, with occasional increases to 200 volts 
to check breakdown. 
contact; however, readjustment of the contacts may be done by removal of 
the relay and subsequent placement in test  cell. 
reiay wus agaiii operated. The above test, therefore, does not indicate life 
time but time to failure. 
These voltage 
End of life was determined by relay failure on any one 
A f t e r  readjustment the 
The relay was determined not to be satisfactory i f  voltage8 
greater than 100 volts were to be switched. 
Conclusions : 
It was decided that to provide the greatest amount of reliability 
and ,operating flexibility that the A C  and DC measurement busses be separated. 
Since the AC measurements a r e  high voltage measurements, i .  e.  above 200 
volts peak 150 volts RMS, and the settling time is 100 milliaeconds for a 
measurement, 'the Clare re lay  was determined to be suitable. 
urements below 60 volts \vi11 use the James Microscan relay which will pro- 
vide the required 400 samples per second rate. 
AI1 DC meas- 
If there a r e  any question8 concerning this report, pleaee contact 
Mr .  K. R.  Grice of out firm at your convenience. 
SYSTEMS ENGINEERING LABORATORIES, 
INCORPORATED 
A.  G. Randolph, Vice President 
Marketing/ Contract I 
AGR / 11 
(12 copies +1 reproducible) 


<ac and dc measurements for relay multiplexer< second quarterly report, period endinging 17 oct. 1964

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server