Refurbished
36Vdc
6.25A & 4.2A Switching Power Supplies
225W and 150W - Burroughs / Unisys B25
Preamble:
This document intended to serve as a brief
guide to technically qualified users familiar with operating mains and low
voltage DC equipments etc. All responsibility for electrical safety and
consequences in use of the equipment rests with the buyer. If in doubt, please
ask (someone who knows).
Warning – be aware - the electrical
voltages internal to this equipment are a hazard
Introduction:
These 2 physically similar PSUs (the 225W
unit has a cooling fan and the 159W unit has both EIA mains input + output
connectors and weighs 1.6kg and the 225W unit weigh 1.95kg) were originally
deployed in running the Burroughs/Unisys B25 Modular-PCs. They have a standard
EIA plug for 120~240Vac input (switch selected) and a RJ8 pole heavy-duty
ribbon connector/cable for the regulated 36V dc output.
Applications:
Typical re-uses include power supplies for small DC
servo motor and stepper motors when used in conjunction with PC based motor
controllers for NC or CNC or robotic projects. The 36V provides headroom for
other voltage regulators (5V, 12V, 15V, 24V) and gives the typical
boost-voltage for running 1 or more concurrent motors in X-Y and X-Y-Z axis
control of small machines and industrial plant etc. within the 4.2A or 6,25A
capacity of the individual power supplies.
Assuming appropriate environment, the units may be
used within their original black plastic cases or just deploying the inner
metal case (6.25A) or open chassis (4.2A) with semi-exposed mains connections
etc..
.
Photographic References:
Detailed photos of the 2 models are here:
<http://ml370/Equipment/Power/Psu/Gallery/>
Note - they may eventually be transferred to the
"Switching" directory:
<http://www.casa.co.nz/Equipment/Power/Psu/Switching/>
Brand: Unisys (alias Burroughs)
Style B25 PS1 3396_7142_1 (225W)
Style B25 PS 3326_0040_1 (225W)
OEM: Elec & Eltek (
Model: 122504-SA-04 (225W)
Specification:
Input:
120~240Vac 50~60Hz
Output:
36Vdc @ 4.4 and 6.25 Amps
Size: 260L x 120W x 75H
(nominal)
Fixing: 4 holes (M4
clearance) on rectangle 233 x 89mm
Weight: 1.6~1.9kg (net)
Refurbishment:
Units are stripped and high-pressure dry-air-blast
cleaned aided with brushes such that any accumulated dust is loosened and
removed. The units are visually inspected before test-voltages are applied.
Partial re-assembly is done to a standard permitting safe performance of the
pre-delivery electrical tests.
Pre-Delivery Tests:
Connect output to a 8~10 Ohm (select to suit
calculations below) 150~200 watt resistor (or equivalent composed of selected
individual smaller resistors in series/parallel) and run on this load for
approximately 10 minutes verifying that the output voltage is 36V and free from
excessive ripple/hum or un-wanted hash by looking on a scope or AC
millivoltmeter.
Units that survive shall be labelled with a CASA
self-adhesive or tie-on label marked TESTED-OK
with the DATE of testing and INITIALS of the tester.
Test Load: 36V @ 6.25A = 225W into 5.76
Ohm load (36V/6.25A = 5.76 Ohms)
Test Load: 36V @ 4.2A = 151.2W into 8.57
Ohm load (36V/4.2A = 8.57 Ohms)
Output Connector Options:
It is proposed that the original RJ8-HD ribbon
connector may be replaced with some more universal connector (D-sub) or
terminal strip to suit the user/system/application. Disassembly, de-soldering
and removing the RJ8 connector and substitution can be undertaken by the
customer or by CASA at additional cost.
Date: 13/02/09
copyright - CASA ModularSystems 2009
Author: AlanD
CASA Modular Systems
Phone: 64-4-9393 777
Fax: 04-9393 778