SCOPE OF MANUAL. This instruction manual covers the installation and operation of the Kepco RAX 100W Series of Switch-
ing Power Supplies. For service information, please refer to the Service Manual for the RAX 100W Series, which can be purchased either from your Kepco Representative, or by writing directly to: Kepco Inc. 131-38 Sanford Avenue, Flushing, New York
11352, U.S.A. When ordering a Service Manual, please state Model Designation and Serial Number of your RAX power
supply. This information can be found on the nameplate of the unit.
DESCRIPTION. The Kepco RAX 100W Series consists of seven models of switching power supplies, with a single output as
shown in Table 1. Units may be operated with either 115V a-c or 230V a-c 47-440Hz input. They will also operate on 240V to
370V d-c input. The RAX 100W Series employs a light weight ferrite core with 140 KHz switching frequency. Regulation is provided by pulse width modulation. A FET power stage, operating in the forward conversion mode provides a smooth isolated d-c
output. A triac “soft-start” circuit prevents excessive turn-on current surge. Overvoltage protection and optically isolated remote
TTL on-off control is provided. Current limiting with automatic recovery from short circuit is featured. Units are enclosed in a
wrap-around aluminum case with an LED “output present” light visible on the terminal side of the case.
Table 1 contains specifications and operating limits of individual RAX 100W Series models. Section II (ollowing) contains specifications and operating limits common to all RAX 100W Series Models.
II — SPECIFICATIONS
CAUTION: UNIT IS SET
TO 115V AC OPERATION
The following specifications are at nominal input voltages at 25°C unless otherwise specified.
TABLE 1. OUTPUT RATINGS AND SPECIFICATIONS, RAX 100W SERIES
MODEL
OUTPUT VOLTS, d-c
ADJUSTMENT RANGE
MAXIMUM
OUTPUT
RATINGS
(AMPS,
WATTS)
CURRENT LIMIT (AMPS)
OVP RANGE (VOLTS)
RIPPLE
AND
NOISE
(mV p-p)
(1) Change of current setting with the specified variations for operating temperatures and source input voltage is within ±10% of the rated values.
(2) Source component 2x source frequency, and switching component approximately 140KHz.
(3) Measured with a 50 MHz bandwidth.
115V a-c input selection, 80V a-c min. (82V a-c min. for model RAX 28-3.5K)
230V a-c input selection, 160V a-c min. (164V a-c min. for model RAX 28-3.5K)
320V d-c input selection, 220V d-c min. (Jumper in 230V a-c position)
INPUT CURRENT: (maximum load at 50°C with nominal output voltage):
TRANSIENT RECOVERY: A step load change from 50% to 100% of rated load in 50 microseconds or more, produces no
more than 4% output voltage excursion. Recovery to 1% of the original voltage is less than 1 millisecond.
OUTPUT HOLDING TIME: Output is maintained for 20 milliseconds minimum upon input interruption (30 milliseconds typical) with nominal input voltage and output load at 50°C current rating.
OVERVOLTAGE PROTECTION: Fixed, factory set. See Table 1. The overvoltage circuit is reset by interrupting input for
approximately 15 seconds.
OPERATING TEMPERATURE: 0 -71°C. See the derating graph, Figure 1.
STORAGE TEMPERATURE: -20°C to + 75°C.
HUMIDITY: 20% to 95% relative humidity, noncondensing
Between input and output terminals, 3.75 KV a-c for 1 minute (with Y-capacitors removed).
Between input and output or chassis, 2000V a-c for 1 minute.
Between output terminals and chassis, 500V a-c for 1 minute.
INSULATION RESISTANCE: Between output and chassis, 100 megohms minimum (500V d-c)
LEAKAGE CURRENT:
0.5mA max at 120V a-c (U.L. Method)
0.75mA max at 240V d-c (U.L./VDE Method)
VIBRATION: Three Axes:
5-10 Hz., 10 mm amplitude
10-55 Hz., 2g
SHOCK: Three axes, 20g, 11 ms ±5msec pulse duration
2
KEPCO, INC. " 131-38 SANFORD AVENUE " FLUSHING, NY. 11352 U.S.A. " TEL (718) 461-7000 "
SAFETY: All units designed to meet UL 1950D3, UL 478, CSA Electrical Bulletin 1402C, VDE 0806, TÜV Rheinland
EN60950 and IEC 950 Safety Standards. RAX are CE marked per the Low Voltage Directive (LVD), EN60950. [The standards do not apply with DC input operation]..
REMOTE ERROR SENSING: RAX 3.3-20K and 5-20K models, up to 0.25V per load wire. All other models, up to 0.4V per
load wire.The power supply is factory set with links in place.
REMOTE CONTROL ON/OFF:
“High,” 2.4V-24V (or open), unit ON
“Low,” 0.0V-0.4V (or closed), unit OFF
When Remote Control (RC) is at “Low” level, the output voltage remains Vo <0.5V
Vo <5% of nominal output for 12, 15, 24, 28, and 48 volt models
III — OPERATION UNIT WILL NOT WORK WITH SENSE LEADS DISCONNECTED (SEE FIG. 2).
INSTALLING THE POWER SUPPLY: Refer to Figure 4. The unit may be mounted on one of the three mounting surfaces.
Mounting holes are provided for each mounting style. The air surrounding the power supply must not exceed the ambient values given in the graph in Figure 1.
CONNECTING AND SWITCHING THE LOAD: The load is connected as shown in links must therefore be removed from the
sense terminals.
SELECTING INPUT VOLTAGE: Input voltage is selected with a jumper. Refer to Figure 3. The power supply is delivered
for 120V a-c operation. Change the jumper to the position marked “230V” to operate the unit from a nominal 220-240V ac or 320V d-c source.
CHANGING FUSES: Remove the cover to replace a fuse. The fuse holder will accept two sizes, either:
KEPCO P/N: 541-0072 or Manufacturer SAN-O P/N SS2-5A (1/4” x 1-1/4”)
KEPCO P/N: 541-0102 or Manufacturer SAN-O P/N Type EQ-5A (5mm x 20mm)
An additional thermal fuse protects the turn-on resistor R1. Refer to Figure 3. Replace this fuse with UCHIHASHI P/N U21 or
KEPCO P/N 541-0086.
VOLTAGE ADJUSTMENT: The unit is provided with a voltage adjustment control. To adjust voltage, first place the unit under
an operating load, then monitor the + and - sense terminals with a precision voltmeter and turn the voltage control to the
desired operating value. Refer to Table 1 for Adjustment Range.
REMOTE TURN-ON TURN-OFF When power is on at the source the unit may be turned on or off with the remote control feature. The output of the remote turn-on/off RC (remote control) terminals operates at TTL logic levels (2.4V-24V “high” and 0.0
to 0.4V “low”). The unit is turned off by bringing the RC terminals to “low” logic level with a switch or solid state device. If the
remote on/off feature is not desired, the terminals should be left open.
LINKS
(SEE NOTE)
NOTE:
THE SENSE LEADS MUST NEVER BE DISCONNECTED FROM THE OUTPUT. IF THE
SENSE LEADS ARE ALLOWED TO FLOAT FREE OF THE OUTPUT, THE OUTPUT VOLTAGE WILL RISE TO THE OVERVOLTAGE POINT AND THE UNIT WILL SHUT DOWN.
FOR REMOTE SENSING CONNECT THE SENSE TERMINALS TO THE LOAD AS
•
SHOWN, AND REMOVE THE TWO SENSING LINKS.
FOR LOCAL SENSING LEAVE THE SENSING LINKS IN PLACE AND CONNECT
•
THE LOAD DIRECTLY TO THE BUS BAR.
FIGURE 1. TEMPERATURE DERATING FIGURE 2. CONNECTING THE LOAD WITH ERROR SENSING
KEPCO, INC. " 131-38 SANFORD AVENUE " FLUSHING, NY. 11352 U.S.A. " TEL (718) 461-7000 "