Fastbus Supply Performance Tests

After picking up the surplus Fastbus material from SLAC in September 1994, the supplies and crates were tested for functionality and durability. For comparing the results, there was also a test setup available, borrowed by the HEP group at the UW. It consisted of a Kinetic Systems Fastbus crate and a "Test Bench Power Supply" (SLAC model 135-866).

"Test Bench" supply (SLAC 135-866) burn-in test

(performed Dec. 18, 1994)

modules in crate	120 VAC input		DC output currents
modules in crate	current	power	@ +5 V	@ -5.2 V
no module	0.45 A	54 VA	0	0
BiRa I/O module	0.58 A	70 VA	2 A	2 A
+ Display module 00A6	0.69 A	83 VA	3 A	3.5 A
+ 1879 module	1.11 A	133 VA	8.5 A	7.0 A
+ 1879 module (2nd)	1.68 A	202 VA	16.5 A	11.0 A
+ 1879 module (3rd)	2.17 A	260 VA	22.5 A	15.0 A
+ 1879 module (4th)	2.64 A	317 VA	28.0 A	19.0 A
+ 1879 module (5th)	3.13 A	376 VA	34.0 A	23.0 A
+ 1885 module	3.60 A	432 VA	36.5 A	25.5 A
+ 1885 module (2nd)	4.10 A	492 VA	39.0 A	28.0 A
+ 1810 module	4.46 A	535 VA	40.0 A	33.0 A

where:

1879 module = LeCroy 1879 TDC (96 inputs)
1885 module = LeCroy 1885 ADC (96 inputs)
1810 module = LeCroy 1810 CAT (calibration for 1879 + 1885)

Power-up tests with type 1 supply (SLAC 135-970)

a) with stable 120 VAC input

(performed Dec. 19, 1994)

loads in crate	120 VAC input		DC output currents			efficiency: input/output power
loads in crate	current	power	@ +5 V	@ -5.2 V	@ -2 V	efficiency: input/output power
standby (before reset)	0.20 A	24 VA	-	-	-	-
standby (after reset)	0.24 A	29 VA	-	-	-	-
power on, no module	2.36 A	283 VA	0	0	0	0
1 * 1879 module	3.08 A	370 VA	8.1 A	6.0 A	4.2 A	22 %
2 * 1879 module	3.70 A	444 VA	16.5 A	10.0 A	7.5 A	34 %
3 * 1879 module	4.34 A	521 VA	25.0 A	14.7 A	10.5 A	43 %
4 * 1879 module	4.95 A	594 VA	33.0 A	18.6 A	12.9 A	48 %
5 * 1879 module	5.54 A	665 VA	40.5 A	22.5 A	15.0 A	53 %
5 * 1879 + 1 * 1885	6.00 A	720 VA	43.2 A	25.5 A	16.2 A	54 %
5 * 1879 + 2 * 1885	6.43 A	772 VA	45.9 A	28.5 A	16.8 A	54 %
5 * 1879 + 3 * 1885	6.90 A	828 VA	48.6 A	31.2 A	18.0 A	54 %
5 * 1879 + 4 * 1885	7.37 A	884 VA	51.6 A	33.9 A	18.9 A	54 %
51879 + 41885 + 1810	7.75 A	930 VA	52.2 A	39.0 A	21.9 A	56 %
61879 + 41885 + 1810	8.44 A	1013 VA	60.3 A	43.2 A	24.9 A	58 %
71879 + 41885 + 1810	9.16 A	1099 VA	68.7 A	47.6 A	28.8 A	60 %

The DC output voltages appeared to be very stable during the whole test, with no measurable fluctuations !

Note: The whole unit is draining approx. 290 Wastts of power just to maintain itself. E.g. each of the NJE power blocks (3 of them in this unit) has its own cooling fan which each of them consuming approx. 35 Watts alone.

b) with variable AC input

(performed Jan. 11, 1995)

Purpose of this test: Check if these modules will work with the Japanese AC voltages at the SuperK experiment - just in case only standard voltages (100 VAC / 60 Hz) are supplied over there.

During this test, the crate was loaded with:

7 * 1879 TDC modules,
4 * 1885 ADC modules, and
1 * 1810 CAT module

Thus, the total DC output load was approx. 660 Watts.

AC input			efficiency	DC output voltages
voltage	current	power load	efficiency	+5 V	-5.2 V	-2 V	+15 V	-15 V
125.2 V	8.64 A	1081 VA	61 %	all stable
120.5 V	8.74 A	1053 VA	63 %	all stable
115.3 V	8.92 A	1028 VA	64 %	all stable
110.6 V	9.11 A	1008 VA	65 %	all stable
105.0 V	9.42 A	989 VA	67 %	stable			+14.9	-15.0
99.7 V	9.71 A	968 VA	68 %	stable			+14.2	-15.0
94.9 V	10.00 A	949 VA	69 %	stable			+13.0	-14.8
89.6 V	10.31 A	924 VA	71 %	stable			+11.7	-14.0
84.9 V	10.48 A	889 VA	74 %	stable			+10.5	-12.8

Remark: No overheating or any other failure during the test period of approx. one hour.

Conclusion:

Safe and acceptable operations possible for AC voltages from 100...125 Volts !
Below 100 VAC, the +/-15 V ouputs are too unstable to be acceptable for long term operations.

Picture of the test setup in the lab:

FB supply test setup

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