M455-1/GRC-206 Power Source

© Brooke Clarke 2007 - 2009


M455-1 GRC-206 Power
                Source
M455-1 GRC-206 Power
                Source Inside View
M455-1 Powered from
                AC Line
M455-1 GRC-206 Power Source
M455-1 Inside View
Power On, See Output Voltage Tables

M455-1 Output
              Cable


Background
Description
    Front Panel
    Not Working Yet  there's probably some additional connection needed.
7 May 2009
IDEA (J3 & J4 are for remote On/Off) - Connect:
 J3-A to J4-A
J3-C to J4-B
    Rear Panel
    Circuit
    Connector p/n
Output Voltages
Manual 
Links

Background

The PP-2953 (see TM 11-6130-233-12) has been around for some time and is carried by surplus military radio dealers but it weighs 40 pounds and is 14x14x7" in size.  It's a linear supply.  So I've been looking for a more modern source of "24 Volts" to power my military radios.  One attempt was the SIAC M449 External Power Module.  It had the look and feel of what I'm after, but has an output that's good for powering a laptop computer, but not a mil radio.  While learning about the GRC-206 system I found the M455-1 which seems to be exactly what I've been looking for.  Hopefully it's designed to power four mil radios at the same time from either 115 VAC or a "24 Volt" vehicle supply.

The problem is that finding any documents on the GRC-206 system is very difficult.

The GRC-206(V)1, GRC-206(V)2, GRC-206(V)3 & GRC-206(V)4 all could be powered by a 1.5 kw gas DC generator (MEP-025A).  But later versions that were designed to be mounted in a HMMWV and  used a Deisel generator to be compatible with the fuel used in the HMMWV, BUT the MEP-802A is a 5 kw AC generator so something needs to convert the AC to about 30 Volts DC with maybe 50 Amps capacity.  I think this is that box.  The GRC-206 page for the MT-6250 has links  to the other GRC-206 components.  Note that it's wastful to use a 5 kw gen set to provide less than 1.5 kw.

Note that the military change over to diesel fuel was completed in year 2000 (was started years prior).  The manufacture date on this power supply is 1997 week 11 (early March) but it was supplied on a contract dated year 2001.

Note that instead of using a huge connector, like on the SB-4151 Power Distrubution Unit, it uses smaller connectors with many pins wired in parallel to get the needed current capacity.

Description

From the NSN the following description is found:
NSN 6130-01-436-1099
The outputs are:
#1: 20 - 30 VDC @ __?__ Amps
#2: 8 VDC @ __?__ Amps
#3: 20 - 30 VDC @ __?__ Amps
I think this is a dual input supply that accepts world wide AC power (99 - 262 V @ 47 - 440 Hz) as the primary source and if there's no primary source uses a secondary 18 to 40 V vehicle source.  

This is a cast metal box that's mostly heat sink fins about 5x5x9 1/2" and weighing 8 pounds.

Compare to PP-2953

Both supply Mil Vehicle "24 VDC"

PP-2953
PP-6224
M455-1
Size
35 x 34 x 16"
14x12x6.75
5 x 5 x 9.5"
Volume cu in
18,496
1,134
237
Weight
39
34.5
8
Power Out
10 A
25A
50 A1
Note 1 : To be measured

Government Description

Name Jack
Value
Output Voltage Rating J2
J3
J1
20.0 DCV Min & 30.0 DCV Max 1st Power Output
20.0 DCV Min & 30.0 DCV Max 2nd Power Output
8.0 DCV Nominal 3rd Power Output
Input Voltage Rating J5
J4
98.9 ACV Min & 262.2 ACV Max 1st Alternate Operating Power Rqmt
18.0 DCV Min & 40.0   DCV Max 2nd Alternate Operating Power Rqmt
Input Frequency Rating J5
47.0 Hz Min & 440.0 Hz Max 1st Alternate Operating Power Rqmt
Input Phase
Single 1st Alternate Operating Power Rqmt
Operating Ambient Temp Range
-40.0 TO 68.0 Deg Celsius
Features Provided
Over Voltage Protector & EMI Filter & Circuit Breaker
Special Features
Self-contained unit mounted in electrical equipment mounting base, MT-6250B/GRC-206;
Provides operational voltages to a variety of hand-held & portable devices
III Part name assigned by controlling agency
Tactical Air Control Party (TACP) Power Ssupply
The Manufacturers data

Manufacturers code
06481


PMIC Critical ADPE ESDC HMIC DEMIL SA SOS AAC QUP UI PRICE SIC CIIC RepCode MgmtCntrl PhraseData
U X 0
N B DF FLZ C 1 EA 16,317.29 0 U T SF8RY-N

Power Analysis

Generator

A 1.5 kw generator might have an output voltage between 20 and 30 VDC with corresponding current of 62.5 to 50 Amps.

GRC-206

Main circuit breaker trips at 50 Amps corresponding to 1500 Watts if at 30 volts.
The AM-7148 can consume up to 19 Amps.

Connectors

The connector contacts are rated for the same current as a wire whose AWG number matches the contact size number.

Note the AC line input has no problem since at 115 Vac only 13 amps are required to get 1500 Watts.  Half that if the input is 230 VAC.
It's the DC connections that may have limitations.
Box
Description
Jack
Cable
Connector
amps/
pin
Total
Amps
M455-1
+24 to 30 DC Out
J2
MS3116F14-19PX 10
70
M455-1 +24 to 30 DC Out
J3
MS3106A14S-2P 22
22
M455-1 +8 DC Out J1
KTP06B8-33P 10
10

M455-1 +18 to 40 DC In
J4
MS3106A14S-2S 22
22

SB-4151 System DC Input
J4 or J5 MS3106R-24-22S 46
46


Front Panel

Label

MPS Milpower Source Inc.
Belmont, NH 03220
Part No.:                  M455-1
Mfg. Cage Code:      0B7R6
Serial No.:               202
Mfg. date:            9711
NSN:                      6130-01-436-1099
Rev: A B C D E F G H

J1 - 8 VDC Output

This will drive a Handheld Terminal Unit (HTU) such as the PSG-9.
MS3114E8-33S with 3 sockets.
All terminals are floating with respect to chassis ground.
A - red
B - black - return
C - blue - return

J2 -  High Current +30 Volt Output

Cabled to the GRC-206 Power Distrubution box J5 Aux input connector.
62GB-5067-14-19SX with 19 sockets (Note this is a Great Britian series mil power connector, why?)
Positive
A  B  C  D  J  K  L  M
Nagative
E  H  R  S  T  U  V
???
F  G 
Chassis Gnd
N  P

MS3116F14-19PX
          Internal View When making up this cable it's tricky to feed each wire through the rubber weather seal since each wire must go to the correct hole AND can not cross over any other wires on the way otherwise you can not seat the weather seal.  After the cable clamp was tightened the connector does not want to mate with the power supply.  I think the reason may be a solder bump on a pin is getting pushed by the weather seal causing the pin to move just enough to by out of line.  Next step is to just pull the weather seal back and have a look with the stereo zoom microscope.

The problem was the tips of the male pins.  They should be hemispherical but were dinged up.  The rough spots were catching on the female socket edges.  A little dressing of the pins with a jewelers file fixed it.

Not Working Yet

27 Fb 2009 - When wired with just the Positive and Negative  wires (i.e. no connection to F or G) there is 30 Volts present at the output, but it does not supply any current, will not light an aircraft landing lamp. 

M455-1 Power Supply back of front
                panel The flathead screws holding on the top and front panels were probably installed with a power screwdriver (Poz 1) so are easy to strip the head.  Best if a drop of Kroil is placed on each screw and allowed to sit awhile before trying to remove them.  One of the front panel screws was munged up.  A few attempts at using just the driver bit and a hammer to reform the Poz 1 shape and trying to unscrew it were unsuccessful.  But after putting a drop of Kroil then a few whacks with the hammer the screw was loose and could be removed using just my fingers on the bit (no driver needed) so it's much better to start with the Kroil than use it later.

The D-sub connector needs to be disconnected prior to hinging out the front panel.  The black wire goes to switch LINE and the red wire goes to switch LOAD and after they are disconnected the front panel is free of the chassis allowing the back of J2 to be inspected.

Three pins of the DB-15 connector are used for the high current contacts, but as far as I can tell they are rated for only 5 Amps per pin allowing thus supporting only 15 Amps.
The 4550 landing light is rated at 28 Volts 250 Watts, i.e. just under 9 amps so should light.
M455-1 Power Supply Back of J2

J2 Back Side


The following pins are visibily connected:
C & D
M, L, K & J
N & P = Chassis Ground (trace under paper label with screw)
R, V, U, E, S, T & H

visibily isolated are:
A, B,

 F & G = spares no connection

So the wiring shown above is correct and there's no sense pins on this connector.

J3 - 30 Volt DC Out

which has a 14S-2 core with 4 sockets
J3 and J4 look like DC chaining connectors
A = red +30 V
B = no connection
C = black - J2-EHRSTUV - Ground
D = blue Chassis Ground
Limited to 22 Amps because of the single pin

J4 - DC Input

which has a  14S-2 core with 4 pins
All terminals are floating with respect to chassis ground.
A = red Breaker +30 In
B = black return for 30 volts
C = no connection
D = no connection
Note this input can only supply 22 Amps so can not be used to power the GRC-206 system.  That means it's use is to backup J1.  That may mean that J1 is intended to power something like the PSG-9 or other small computer.

Power On-OFF breaker switch DPST

 One pole for DC and one for AC.

Power On LED

Rear Panel

J5 - AC Input

accepts world wide AC power (99 - 262 V @ 47 - 440 Hz) as the primary source
MS474W12-8P with 8 pins. 2- orange, 2-black & 2- blue wires.  The blue & black wires might be going through a filter network including surge suppression. (EMP?).
A + B =  Breaker =AC  line hot (guess)
C + D = AC line neutral
E + F = Gnd orange wires
G = nc (guess)
H = nc (guess)

Chassis GND = a hole tapped for 6-32

Circuit

The classical way to do this is to full wave bridge rectify the input AC line and charge up some big caps (maybe blue Philips 169 52102, M HP 9616, 40/105/56?).  Hundreds of volts are on these caps and that drives one or more switching power supplies which utilize toroid transformers to get line isolation.  The printed circuits have the large through hole components on the top side and Surface Mount ICs on the bottom side.

The right side PCB is probably the AC Line driven supply.  There's a DB-9 connector on this board that has 9 wires going to the left side PCB and they all are orange but they are not all shorted to each other.  The left side PCB has a DB-15 connector with wires going to the front panel PCB.  Although there's different wire colors (3 blue, 7 yellow & 5 gray) there appear to be direct connections between the colors, maybe a force and sense system to better regulate the voltage right at the front panel.

Connector p/n

 Panel
Jack #
Photo
Panel
Conn
Panel
Desc
Cable Plug
J1
M455-1 J1
MS3114E8-33S
3 Sockets
KTP06B8-33P
J2
M455-1 J2
62GB-5067-14-19SX 19 Sockets
MS3116F14-19PX
J3
M455-1 J3 14S-2 4 Sockets
Re-Key1
MS3106A14S-2P
The core is rotated
J4
M455-1 J2 14S-2 4 Pins
Re-Key1
MS3106A14S-2S
The core is rotated
J5
M455-1 J5
MS3474W12-8P 8 Pins

KPTO6B12-8S
12 Dec 2007  - made up the A.C. line cord for J5.  DC measurements between all three (hot, neutral, ground) shows over 14 M Ohm resistance, which is a good thing.
For a photo of the P5 connector while it was being assembled see the Hints & Tips page about using solder wick to get the solder out of the pin on this used connector.
Note 1 - after removing the core you can use a hacksaw to cut a new position key.

Output Voltages

J1 8 VDC Out or Control?

The GRC-206 system has a provision for operator control of DC power and this may be some type of control rather than an output.
Or it may be a power supply for a small computer, like the Handheld Terminal PSG-9.

Red       Blk->
v      
A
B
C
Gnd
A
-
+8
+8
-8
B

-
0
-16
C


-
-16
Gnd



-

J2

This may be a way to get higher current carrying capacity in a connector with small diameter pins.  Takes less space than a connector with much larger pins.
Notice that 7 pins are all tied toghther.  These are 20 ga pins rated for 10 amps so this is a 70 Amp ground connection.
Red       Blk->
v     
A + B + C + D E + H + R + S + T + U + V
J3-C
F G J + K + L + M N & P
gnd
A + B + C + D -
29
0
0
0
+10
E + H + R + S + T + U + V = J3-C
-
0
0
-29
-17
F


-
0
0
0
G



-
0
0
J + K + L + M



-
+10
N & P - Gnd




-
  Black (Ground) = E + H + R + S + T + U + V  (good for a total of 70 Amps)
  Red (+30) = A + B + C + D (good for 40 Amps)

J3 12 & 24VDC Out

These are 16 ga contacts good for 22 Amps each.  If the Red wires from J2 and J3 are tied toghther then the capacity would be 56 Amps total.

Red       Blk->
v              
A
B
C
D
gnd
A
-

+29
+10
+10
B

-
0
0
0
C


-
-15
-15
D



-
0
gnd




-
 
A: Red & C: Black
At least 6 amps at 28 Volts, 1 Amp @ 29.6 Volts.  Limited by EL1132 Electronic Load.

Manual

35C1-2-1223-1 M455-1  OPERATION AND MAINTENANCE INST

Links

Mike Murphy Surplus -U.S. Issue Com Equip - O-1814 -

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  page created 26 Nov 2007