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E. Technical Description of ± 15VDC/ ± 24VDC Power Supply # 10401415
The power supplied to this board must be provided by an externally mounted transformer
connected to Pins 5 and 6, center tap to Pin 7 or 8, of header connector. This transformer
should provide 18 VAC between Pins 5 and 7 or 8, and 18 VAC between Pins 6 and 7 or
8, 36 VAC should be seen between Pins 5 and 6. The center tap of this transformer is
connected to circuit common. Full wave bridge rectifier DB 201 (1 amp max) serves to
provide unreg24 VDC and -24 VDC with respect to circuit common
approximately 50 VDC may be from the negative to the positive side of this bridge. The
+24 VDC output (Pin 4 of header connector) is filtered by C202 (2200µfd) and the -24
VDC output (Pin 3 of header connector) is filtered by C203 (500 µfd). The +24 VDC
output also supplies the input to adjustable regulator IC 201 (1.5 amp max) to provide the
+15 VDC output (Pin 1 of header connector). This regulator may be adjusted from
approxi6.5 VDC +16 VDC (with respect to circuit common) by POT 201 (500
1 turn). The -24 VDC output supplies the input to regulator IC 202 used to provide the
-15VDC output Pin 2 of header connector. The ± 24 VDC outputs are non-regulated and
will vary with input AC voltage and/or load. The ± 15 VDC outputs are regulated and
should not vary more than ± 0.5 volts. The limiting factor for available output current
may be dictated by the external transformer connected to this power supply. All of the
components used are rated for a minimum of 1 Amp. However, if the transformer used is
rated for less than 1 Amp, the rating of the transformer will dictate available output
current.
F. General Description of Relay Board # 10401416
This board houses 2-4 Pole double throw 24 VDC (coil) relays. Each contact set on both
relays is electrically isolated from each other.
G. Technical Description of Relay Board # 10401416
Relay CR201’s coil and contacts run to Pins 15 through 28 of the header connector. Relay
CR202’s coil and contacts run to Pins 1 through 14 of the header connector. A diode is
mounted in parallel with each relay coil to eliminate an induced surge generated by
turning off the inductive load of the relay’s coil. This diode also dictates the polarity with
which each coil is powered. CR202’s coil is connected to Pins 1 and 3 of the header
connector. The diode in parallel with CR202 is D203. The anode of D203 is connected
to Pin 1, and the cathode of D203 is connected to Pin 3 of the header connector. The
polarity of the power used to turn on CR202 must make the diode (D203) reversed bias.
(Pin 1 of the header connector must be negative with respect to Pin 3 of the header
connector.)
Summary of Contents for 942B
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