Electrical Test Instruments, LLC.
Product Description and Specifications
2 kVA ACDC Power Supply Model ACDC-20
Overview:
This is a portable AC and DC power supply intended for circuit breaker charging
motors and other general-purpose applications. It will provide variable AC voltages up
to 560 VAC and DC voltages up to 480 VDC, at 2 kVA. It will be in an enclosure
approximately 21” x 18” x 12”, and weighs 115 lb.
Basic Description and Operation:
This instrument is housed in a rugged waterproof case with a hinged lid. The input
connection is by way of a recessed three prong male inlet compatible with standard
IEC cords. The input is protected and controlled by a 20-amp single pole circuit
breaker. When it is turned ON, a dual-deck variable autotransformer (Vernier) is
energized, as well as a 0 –600 volt digital meter. The output arm(s) are protected by a
two-pole breaker. The variable output of the Vernier is connected to the primaries of
four 700 VA toroidal transformers. The secondaries are connected in series and
parallel configuration by means of a multi-deck six position selector switch. The AC
output is monitored by the 0 - 600 VAC digital meter. An additional resistor is added
in DC mode to read the DC output voltage for open circuit or resistive loads.
The output is controlled by means of a three-position rotary switch. It has maintained,
momentary, and center OFF positions. When turned ON, a relay is energized and the
Output On lamp is illuminated. The contacts of the relay provide AC voltage directly
to one pair of yellow binding posts and through a full-wave bridge rectifier to provide
DC to a pair of red and black binding posts.
A 20 kOhm load resistance is connected to the DC output along with a 12-volt Zener
diode. This provides a 3 - 12 watt load for the DC output.
This power supply has no filter capacitors on the 240VDC and 480VDC Output modes
and is intended to be operated with no load capacitance. The actual AC voltage will
drop by as much as 11% under rated load, and the voltmeter will read the actual
voltage. The calibration resistor for DC will be set so that the voltmeter reads the
expected DC output at no load, but this will drop by 11% or more depending on actual
load. Snubbers are connected across the output terminals to reduce noise and high
voltage spikes when connected to inductive loads.
The TIMER jacks may be used to start an external timer when the output voltage is
applied to the load. These contacts consist of a solid-state relay rated at 0.1 amps and
200 V.
The Remote Jacks may be used to remotely turn output on via solid state relay these
are dry contacts.
