KEPCO RAX 50W User Manual

INSTRUCTION MANUAL

KEPCO

An ISO 9001 Company.

RAX

50 WATT SINGLE OUTPUT

SWITCHING POWER SUPPLIES

I — INTRODUCTION

SCOPE OF MANUAL.

Power Supplies. For service information, please refer to the Service Manual for the RAX 50W 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
This information can be found on the nameplate of the unit.

DESCRIPTION.

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 50W 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 50W Series models. Section II (following) contains specifi­cations and operating limits common to all RAX 50W Series Models.

II — SPECIFICATIONS

This instruction manual covers the installation and operation of the Kepco RAX 50W Series of Switching

Model Designation and Serial Number of your RAX power supply

The Kepco RAX 50W Series consists of seven models of switching power supplies, with a single output as

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 50W SERIES

MODEL

OUTPUT VOLTS, d-c

ADJUSTMENT RANGE

MAXIMUM

OUTPUT

RAT INGS

(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.

switching (typ)

(2)

switching (max)

50° C amb.

60° C amb.

71° C amb.

source (typ)

source (max)

spike noise

(3)

(max)

INP UT V OLTA GE :

RAX 3.3-10K RAX 5-10K RAX 12-4.2K RAX 15-3.4K RAX 24-2.1K RAX28-1.8K RAX 48-1K

3.3V 5V 12V 15V 24V 28V 48V

1.8 - 3.6V 4.0 - 5.5V 8.4 - 13.2V 12.0 - 16.5V 16.8 - 26.4V 19.6 -30.8V 32.6 - 52.8V

10.0A/33W 10.0A/50W 4.2A/50.4W 3.4A/51W 2.1A/50.4W 1.8A/50.4W 1.0A/48W

7.0A/23.1W 7.0A/35W 2.9A/35.3W 2.4A/35.7W 1.5A/35.3W 1.3A/35.3W 0.7A/33.6W

4.0A/13.2W 4.0A/20W 1.7A/20.1W 1.4A/20.4W 0.8A/20.1W 0.72A/20.2W 0.4A/19.2W

(1)

10.5 -11.0 10.5 -11.0 4.5 - 4.8 3.6 - 3.9 2.3 - 2.5 2.0 - 2.2 1.1 - 1.3

3.9 - 4.8 6.0 - 6.9 13.7 - 15.7 17.0 - 19.5 27.0 - 30.5 32.0 - 35.0 55.0 - 63.0

5 5 15 15 25 30 35

10 10 30 30 40 60 90

25 25 25 25 25 25 25

40 40 50 50 60 60 60

100 100 170 200 290 330 530

(Jumper selectable, see Section III, FIG. 3):
120V a-c nominal, range: 85 -132V a-c
220-240V a-c nominal, range: 170 -264V a-c
320V d-c nominal, range: 240 -370V d-c
For d-c input the jumper is placed in the 230V position.

INPUT SOURCE FREQUENCY:

Nominal 50/60 Hz; Range 47-440 Hz. (At 400 Hz the leakage current exceeds the VDE safety specification limit.)

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BROWNOUT VOLTAGE:

115V a-c input selection, 80V a-c min. (82V a-c min. for model RAX 28-1.8K)
230V a-c input selection, 160V a-c min. (164V a-c min. for model RAX 28-1.8K)
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):

INPUT SOURCE NOMINAL INPUT VOLTAGE MINIMUM INPUT VOLTAGE

120 V a-c input selection 1.2A typ. - 1.6A max. 1.3A typ. - 1.8A max.

220-240V a-c input selection 0.6A typ. - 0.8A max. 0.7A typ. - 0.9A max.

d-c input selection 0.4A max. (320V input) 0.6A max. (240V input)

INPUT PROTECTION AND SOFT START:

by an input fuse. Fuse value 3.15A.

INPUT SURGE:

At 25°C from cold start:

NOTE: There are two input surges at turn-on:

INPUT SOURCE FIRST SURGE (5ms max.) SECOND SURGE (3ms max.)

120 V a-c input selection 17A max. 5A typ.

220-240V a-c input selection 34A max. 3A typ.

320V d-c input selection 34A max. 3A typ.

EFFICIENCY:

75% typical

STABILIZATION:

CHARACTERISTIC TYPICAL MAXIMUM

Source Effect (min - max) 0.8% 1.5%

Load Effect, measured at sensing terminals (10% - 100% load change) 0.8% 1.5%

Temperature effect (0 to 71°C) 1.0% 2.0%

Combined effect (envelope) 2.0% 4.0%

Drift (8 hr. at 25°C) 0.1% 0.5%

A triac soft start circuit reduces start-up surge. Units are protected against shorts

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 typi-

cal) 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:

STORAGE TEMPERATURE:

HUMIDITY:

20% to 95% relative humidity, noncondensing

0 -71°C. See the derating graph, Figure 1.

-20°C to + 75°C.

ALTITUDE:

Operating: 10,000 feet (3048.0m)
Nonoperating: 35,000 feet (10,668m)

ISOLATION:

(at 25°C ambient, 65% relative humidity):
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

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SHOCK:

Three axes, 20g, 11 ms ±5msec pulse duration

EMI CONDUCTED:

SAFETY:

All units designed to meet UL 1950D3, UL 478, CSA Electrical Bulletin 1402C, VDE 0806, TÜV Rheinland EN60950

FCC Class A

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 3.3-10K and 5-10K 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 48V models

III — OPERATION UNIT WILL NOT WORK WITH SENSE LEADS DISCONNECTED (SEE FIG. 2).

INSTALLING THE POWER SUPPLY:

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 terminals to compensate for voltage loss in the connecting wires. The jumper links must therefore be removed from
the sense terminals.

SELECTING INPUT VOLTAGE:

120V a-c operation. Change the jumper to the position marked “230V” to operate the unit from a nominal 220-240V a-c or
320V d-c source.

Refer to Figure 4. The unit may be mounted on one of the three mounting surfaces.

The load is connected as shown in Figure 2. Error sensing may be done at

Input voltage is selected with a jumper. Refer to Figure 3. The power supply is delivered for

CHANGING FUSES:

Remove the cover to replace a fuse. The fuse holder will accept two sizes, either:
KEPCO P/N: 541-0100 or Manufacturer SAN-O P/N ST4-3.15A (1/4” x 1 1/4”)
KEPCO P/N: 541-0101 or Manufacturer SAN-O P/N Type EQ-3.15A (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 NOTES)

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

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FIGURE 3. SIMPLIFIED VIEW, COVER REMOVED FIGURE 4. OUTLINE DRAWING, RAX 50W SERIES

NOTES: 1. Dimensions in parentheses are in millimeters, others are in inches.

6. WEIGHT: 1.8 lbs (0.8 Kg.) max., 1.5lbs. (0.7Kg)

captive flat and lock washer, KEPCO P/N 501-0058.

5. MATERIAL AND FINISH: A) Case is aluminum, phosphate coated; B) Terminal Block is

Polybutylene Terephthalate (black).

2. TOLERANCES: ; ±0.04” (±1.0 mm) unless specified.

3. MOUNTING SCREW PENETRATION: 0.028” (7 mm) maximum.

4. TERMINAL BLOCK: 9 Terminals. KEPCO P/N/ 567-0017. Terminal screws: M4x6 with

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