Chromalox MAXPAC PK480 User manual

PK480
P/N 0037-75428
User's Manual
www.chromalox.com
800-443-2640
© 2002 Chromalox, Inc.

- 1 -
© 2002 Chromalox®, Inc.1-888-996-9258
Thank you for choosing he Chromalox® MaxPac™ - a comple e power con rol solu ion wi h indus ry-bes
price and performance.
For more han 80 years, cus omers have relied on Chromalox for he u mos in quali y and innova ive solu ions
for indus rial hea ing applica ions. Chromalox manufac ures he world’s larges and broades line of elec ric hea
and con rol produc s.
The MaxPac Series SCR Con rollers provide he bes con rol for applica ions where consis en hea er/process
empera ure is cri ical or where fine resolu ion of power is required.
Common MaxPac features include:
• 120 - 575 Vac @ 100 - 1200 Amps
• Isola ed Con rol Circui
• Flexible I/O Power Wiring
• Easy Cus omer In erface
• Remo e Shu down
• Compac Size and Cons ruc ion
• Touch-Safe Design (op ion on 100 - 650 Amp models)
• dv/d Transien Vol age Pro ec ion
• MOV Pro ec ion
• Buil -In Power Dis ribu ion
Features for the MaxPac I, II, and III include:
• Zero Crossover Firing
• Isola ed Con rol Circui
On/Off Con rol Inpu s:
120 hru 240 Vac
5 - 32 Vdc
Dry Con ac Closure
Propor ional (DOT Firing) Inpu s:
4 - 20 mA, 0-5 Vdc, 1 - 5 Vdc, 0 - 10 Vdc
Remo e Manual Adjus
Remo e Au o/Manual Swi ch
• Elec ronically Pro ec ed wi h Tempera ure Warning and Shu down Sys em
• Single- or Three-Cycle Resolu ion (Jumper Selec able)
• Shor ed SCR De ec ion (Op ional)
Features for the MaxPac IP include:
• Phase Angle Firing
• Isola ed Con rol Circui Inpu s
0 - 5 mA, 0 - 20 mA
0 - 50 mA, 1 - 5 mA
4 - 20 mA, 10 - 50 mA
0 - 5 Vdc, 0 - 10 Vdc
• Op ional Curren Limi
• Sof S ar
• Line Vol age Compensa ion
• Zero & Gain Adjus men s
• Buil -In Manual Adjus men
• Curren Limi Adjus men (Op ional)
If you have applica ion ques ions, refer o he Engineering Resource sec ion of our websi e a
www.chromaloxhea ing.com o find he answer you’re looking for, or call one of our applica ion
engineers a 1-888-996-9258 for personal assis ance.

- 2 - © 2002 Chromalox®, Inc. 1-888-996-9258
○○○○○○○○○○○○○○○○○○○
Table of Contents
Section Topic Page
1 ................................................ Impor an Safeguards ...................................................................................... 3
2 ................................................ Descrip ion ...................................................................................................... 4
3 ................................................ Before You Ins all ............................................................................................ 5
4 ................................................ Ins alla ion ....................................................................................................... 6
4.1 ................................ Moun ing ........................................................................................................ 8
4.2 ................................ Wiring ........................................................................................................... 11
4.2.1 ................ Touch-Safe Design ....................................................................................... 11
4.2.2 ................ Cover Removal and Ins alla ion ................................................................... 12
4.2.3 ................ Power/Load Wiring ....................................................................................... 12
4.2.4 ................ Ins rumen Power ......................................................................................... 16
4.2.5 ................ Grounding ..................................................................................................... 16
4.2.6 ................ Command Signal Wiring............................................................................... 17
4.2.7 ................ Calibra ion .................................................................................................... 23
5 ................................................ Specifica ions ............................................................................................... 24
6 ................................................ Main enance ................................................................................................. 25
7 ................................................ Troubleshoo ing ............................................................................................ 26
8 ................................................ Par s and Accessories .................................................................................. 27
9 ................................................ Warran y and Re urn Informa ion ................................................................. 28
10 .............................................. EC Declara ion of Conformi y ....................................................................... 37

- 3 -
© 2002 Chromalox®, Inc.1-888-996-9258
1
Please read all ins ruc ions before ins alling and opera ing your MaxPac™.
To avoid elec rical shock or injury, always remove power before servicing a circui .
Personnel working wi h or near high vol ages should be familiar wi h modern me hods of resusci a ion. Con ac
an area supervisor or safe y personnel for more informa ion.
Throughou he MaxPac User Manual, he safe y aler and he in erna ional elec ric shock/elec rocu ion
symbols will aler you o po en ial hazards. Safe y precau ions should always be followed o reduce he risk of
personal injury o persons from fire and elec rical shock hazards.
Safe y Aler Symbol
In erna ional Shock/Elec rocu ion Symbol
Each safe y message is preceded by a safe y aler symbol and one of hree words: DANGER, WARN-
ING, or CAUTION.
These mean:
○○○○○○○○○○○○○○○○○○○○○○○○
Important Safeguards
You WILL be killed or seriously hur if you do no follow ins ruc ions.
You CAN be killed or seriously hur if you do no follow ins ruc ions.
You CAN be hur if you do no follow ins ruc ions.
DAN ER
WARNIN
CAUTION
Damage Preven ion Messages:
You will see o her IMPORTANT messages ha are proceeded by he word ha are in ended o
help preven damage o he MaxPac™ or o her equipmen . No e ha Damage Preven ion Messages are NOT
accompanied by he Safe y Aler Symbol.
CAUTION

- 4 - © 2002 Chromalox®, Inc. 1-888-996-9258

2
† This can be se o hree cycles ‘On’ / hree cycles ‘Off’ (see sec ion on ins alla ion op ions).
○○○○○○○○○○○○
Description
MaxPac I, II, and III
The Chromalox MaxPac I, II, and III con rollers are highly versa ile SCR Power Paks wi h op ional plug-in
propor ional firing and shor ed SCR de ec ion boards. Firing modes include On/Off and DOT propor ional zero
vol age swi ching. Chromalox exclusive DOT (Demand Orien ed Transfer) firing echnique swi ches he fewes
number of cycles o provide he mos precise zero crossover con rol. A 50% ou pu , he uni ’s ou pu al er-
na es be ween one cycle “On” and one cycle “Off.” A 51%, he ou pu con inues wi h one cycle “On,” one
cycle “Off,” and gradually in egra es one ex ra “On” cycle for he addi ional 1%. This DOT fired echnique also
minimizes empera ure overshoo , empera ure fluc ua ions and helps ex end he load’s elemen life due o
reduced hermal shock.
The power SCR assemblies consis of one, wo, or hree pairs of SCRs connec ed back o back (wi h an
op ional semiconduc or fuse), RC Snubber, and MOV pro ec ion. The firing circui is based on a common On/Off
con rol board wi h plug and play Shor ed SCR and DOT fired plug-in boards. Diagnos ic indica ors are included.
Plug-in erminal blocks for easy cus omer in erface are also provided.
MaxPac IP
The Chromalox MaxPac IP u ilizes Single Phase, Phase Angle firing o modula e power o an induc ive or
resis ive load. Phase Angle con rol has he advan age of propor ioning every cycle hereby providing very fine
resolu ion of power. Fas responding loads in which he resis ance changes as a func ion of empera ure
require Phase Angle con rol. The MaxPac IP offers a Sof S ar fea ure ha assures ha he load power is
gradually increased from zero o he value se by he command signal in he even of a power in errup ion. In
addi ion, op ional Curren Limi is used o pro ec he load, SCR con roller and he o al sys em from large surge
curren s ha could occur a s ar -up.

- 5 -
© 2002 Chromalox®, Inc.1-888-996-9258
3
○○○○○○○○○○○○○○○○○○○
Before You Install
Immedia ely af er receiving your MaxPac I, II, III or IP Series Con roller, visually inspec he shipmen packaging
and record any damage on he shipping documen s. Unpack he con roller and carefully inspec for obvious
damage due o shipmen . If any damage has occurred, YOU mus file a claim wi h he carrier company, since
he carrier company will no accep a claim from he shipper (Chromalox).
Be sure o check he model number and verify ha you have received he correc Model of con roller.
If he con roller is no ins alled and placed in o opera ion immedia ely, i should be s ored in a cool, dry environ-
men . Tempera ure ex remes and excessive mois ure can damage he con roller.
Before choosing a loca ion in which o moun your MaxPac, please consider he following:
Temperature
When moun ing he SCR uni in a con rol panel, a en ion should be paid o he enclosure empera ure.
The SCR is ra ed o perform a i s namepla e curren ra ing in empera ures up o 50˚C (122˚F).
Ensure ha adequa e ven ila ion is provided or some o her me hod of main aining he correc cabine
empera ure is used.
Cleanliness
Careful a en ion mus be paid in areas subjec ed o airborne par icles. The efficiency of he hea sinks
relies on heir conduc ing surfaces being main ained in a clean manner. (See he Main enance Sec ion.)
Dampness
High humidi y or hosing down a uni should be avoided.
Clearance
Choose a loca ion ha will provide adequa e spacing around he uni when moun ed. This will ensure
proper air flow necessary o cool he device.
WARNIN
Hazardous Voltage: Disconnec and lockou power before ins alling
or servicing. Failure o comply could resul in personal injury or
equipmen damage.

- 6 - © 2002 Chromalox®, Inc. 1-888-996-9258
Installation Section
(continuation of page 5)
The forced air design of the MaxPac series allows mounting in any direction. It is essential that air flow through
the enclosure be planned to insure proper cooling.
The 100 amp through 300 amp open design MaxPac allow the input line power to connect from either of two directions.
The output power can only be connected from one direction. The three mounting configurations
are shown below (MaxPac II Three-Phase Two-Leg Shown).
Open designs above 300 amps and all closed designs allow incoming
and outgoing wiring in either direction.
In In
Configuration One
Cool Air In Warm Air Out
Fan Phase 1 Phase 3
or In Out or In Out
Configuration Two
Out Out
In In
Warm Air Out Cool Air In
Phase 1 Phase 3 Fan
or In or In
Configuration Three
Warm Air Out
Out
Phase 3
or In
In
Out
Phase 1
In or In
Fan
Cool Air In

- 7 -
© 2002 Chromalox®, Inc.1-888-996-9258
Installation Section
(
continuation of
p
a
g
e 5
)
Examples of Proper Air Flow
Pagoda Top
Fan
Air
Louvers Louvers
MaxPac
Air
Fan MaxPac
Fan
Enclosure
Air Enclosure
Fan
Filter
Forced Air In
Forced Air Out
Louvers
Since hot air rises naturally, it is not recommended that cooling air ente
r
from the top and exhaust at the bottom of the enclosure.

- 8 - © 2002 Chromalox®, Inc. 1-888-996-9258
FigureFigure
FigureFigure
Figure Drawing NumberDrawing Number
Drawing NumberDrawing Number
Drawing Number ModelModel
ModelModel
Model
FigureFigure
FigureFigure
Figure ModelModel
ModelModel
Model
1 .............. 100A, 150A, & 200A 2-Leg Open Type
1 .............. 100A, 150A, 200A, & 300A 1-Leg Open Type
2 .............. 100A, 150A, & 200A 3-Leg Open Type
3 .............. 300A 2-Leg Open Type
4 .............. 100A, 150A, 200A, 300A & 400A 1-Leg Touch-Safe
4 .............. 400A 1-Leg Open Type
5 .............. 100A, 150A, 200A, 300A & 400A 2-Leg Touch-Safe
5 .............. 400A 2-Leg Open Type
6 .............. 100A, 150A, 200A, 300A & 400A 3-Leg Touch-Safe
6 .............. 300A & 400A 3-Leg Open Type
7 .............. 550A & 650A 1-Leg Touch-Safe
7 .............. 550A & 650A 1-Leg Open Type
8 .............. 550A & 650A 2-Leg Touch-Safe
8 .............. 550A & 650A 2-Leg Open Type
9 .............. 550A & 650A 3-Leg Touch-Safe
9 .............. 550A & 650A 3-Leg Open Type
................ 800-1200 Amp uni s, consul fac ory
4
○○○○○○○○○○○○
Installation
Please read all informa ion in his sec ion before beginning he ins alla ion of your MaxPac.
Ins alla ion of he MaxPac requires hree s eps:
1. Moun ing
2. Power wiring
3. 120 or 230 Vac 50/60hz for ins rumen power. See 4.2.4, pg. 16.
4.1 - Step 1: Mounting
Before moun ing your MaxPac, please read he sec ion i led “Before You Ins all’ on page 5 for a descrip ion of
an ideal environmen for he uni ’s opera ion.
The space required for moun ing he MaxPac Power Pak depends upon he model. The able below refers o
he figures on he following pages. These figures illus ra e he dimensions and moun ing holes for he various
MaxPac Power Pak models. Please refer o hese figures before moun ing your uni .
IMPORTANT: Please no e ha he figures on he following pages are
not drawn to the same scale.

- 9 -
© 2002 Chromalox®, Inc.1-888-996-9258
Figure 1 Figure 2
Figure 3 Figure 4
Figure 5
4.7" [107mm]
0.0" [0mm]
1.0" [25mm]
4.75" [121mm]
8.5" [216mm]
9.5" [241mm]
6.0" [153mm]
7.3" [185mm]
FIRING PACKAGE
FAN END
Ø0.280" [Ø7.11mm]
(6 HOLES)
4.2" [107mm]
0.0" [0mm]
1.0" [25mm]
7.2" [184mm]
13.5" [342mm]
14.5" [368mm]
6.0" [153mm]
7.28" [185mm]
FIRING PACKAGE
FAN END
Ø0.280" [Ø7.11mm]
(6 HOLES)
7.2" [183mm]
0.0" [0mm]
1.3" [33mm]
7.3" [185mm]
13.3" [337mm]
14.6" [371mm]
12.0" [305mm]
13.3" [338mm]
FIRING PACKAGE
FAN END
Ø0.280" [Ø7.11mm]
(6 HOLES)
5.12" [130mm]
0.0" [0mm]
1.3" [33mm]
9.3" [237mm]
13.3" [338mm]
14.6" [371mm]
8.1" [206mm]
9.1" [232mm]
FIRING PACKAGE
FAN END
Ø.3125 [Ø7.94mm]
(8 HOLES)
5.3" [135mm]
8.4" [214mm]
0.0" [0mm]
1.3" [33mm]
9.3" [237mm]
13.3" [338mm]
14.6" [371mm]
14.7" [375mm]
15.75" [400mm]
FIRING PACKAGE
FAN END
Ø.3125" [Ø7.94mm]
(8 HOLES)
5.3" [135mm]

- 10 - © 2002 Chromalox®, Inc. 1-888-996-9258
Figure 9
13.8" [351mm]
0.0" [0mm]
1.3" [33mm]
26.5" [673mm]
16.3" [414mm]
17.6" [448mm]
11.3" [287mm]
25.5" [648mm]
FIRING PACKAGE
FAN END
Ø.3125" [Ø7.94mm]
(8 HOLES)
6.3" [160mm]
Figure 6 Figure 7
Figure 8
11.7" [298mm]
0.0" [0mm]
1.3" [33mm]
9.3" [237mm]
13.31" [338mm]
14.62" [371mm]
21.4" [543mm]
22.4" [568mm]
FIRING PACKAGE
FAN END
Ø.3125" [Ø7.94mm]
(8 HOLES)
5.3" [135mm]
5.8" [148mm]
0.0" [0mm]
1.3" [33mm]
11.3" [28mm]
16.3" [414mm]
17.6" [448mm]
9.5" [241mm]
10.5" [267mm]
FIRING PACKAGE
FAN END
Ø.3125" [Ø7.94mm]
(8 HOLES)
6.3" [160mm]
9.8" [249mm]
0.0" [0mm]
1.3" [33mm]
11.3" [287mm]
16.3" [414mm]
17.6" [448mm]
17.5" [444mm]
18.5" [470mm]
FIRING PACKAGE
FAN END
Ø.3125" [Ø7.94mm]
(8 HOLES)
6.3" [160mm]

- 11 -
© 2002 Chromalox®, Inc.1-888-996-9258
4.2 - Step 2: Wiring
4.2.1 - Touch-Safe Design
If he MaxPac model you purchased is of a Touch-Safe design, follow he s eps on he following page o
ins all he elec rical wiring. This will ensure he wiring is done properly while main aining he Touch-Safe
fea ure. If your MaxPac is of an Open design below 400 Amps, disregard his subsec ion.
The following is a de ailed drawing of a Touch-Safe uni :
Careful a en ion mus be paid when a aching he wiring o he MaxPac o ensure proper and safe opera ion.
This sec ion con ains de ailed informa ion on how o connec he power, resis ive load, ground, and command
signal wiring.
IMPORTANT: Selec ins alla ion wiring ha is in accordance wi h he Na ional
Elec rical Code and any local s andards ha may be applicable.
WARNIN
Hazardous Voltage: Only qualified personnel should perform
elec rical wiring for he MaxPac Power Paks. LETHALLY HIGH
VOLTAGES are associa ed wi h his equipmen and are danger-
ous if improperly ins alled.
COOLING AIR
COOLING AIR
SCR
FUSE
HEATSINK FINS
COVER PROVIDES FOR TOUCH SAFE FEATURE
TOUCH-SAFE COVER PROVIDES WIRE ENTRANCE AND
EXIT THROUGH SEALS COVERING THE WIRE WINDOW.
REMOVAL OF THE TAPE BEHIND THE WINDOWS TO
BE USED ALLOWS WIRES TO PASS. THE TAPE
REMAINS ON UNUSED WINDOWS TO PROVIDE TOUCH
SAFE FEATURE.
BUS BAR DESIGN ALLOWS
FOR WIRING FROM EITHER
DIRECTION AND MULTIPLE
LOAD CIRCUITS
BUS BAR DESIGN ALLOWS
FOR WIRING FROM EITHER
DIRECTION AND MULTIPLE
LOAD CIRCUITS
LONG LIFE, HIGH OUTPUT BALL
BEARING FANS PROVIDE RELIABLE
COOLING

- 12 - © 2002 Chromalox®, Inc. 1-888-996-9258
4.2.3 - Power/Load Wiring
The following illus ra ions depic how o connec he MaxPac o a resis ive or induc ive load. Make sure you refer
o he correc illus ra ion for he MaxPac series you have purchased.
For he power/load drawings:
On open design uni s up o 300 Amps, X1, X2, X3, L1, L2, and L3 refer o copper lugs.
On open design uni s 400 Amps and grea er and all Touch-Safe designs, X1, X2, X3, L1, L2, and L3 refer o
bus bar connec ions.
MaxPac I
4.2.2 - Steps for Touch-Safe Design Cover Removal and Installation
Remove Cover:
1. Loosen he humb screws on bo h ends of he cover.
2. Lif he cover from he base.
Ins all Wiring:
3. A ach he wires o he bus bars in accordance wi h he ins ruc ions in he nex sec ion.
4. Choose he en rance and exi direc ions for he wiring as desired.
5. Af er he wiring is comple e, remove he ape from he inside of he wire gaske s of he
windows ha he power wiring will en er or exi .
Replace Cover:
6. Angle he end of he cover wi hou screws owards he “fan-end” of he uni .
7. Slip ha end in o place firs while allowing he wiring o pass hrough he desired windows.
8. Slip he opposi e end of he cover in o place.
9. Tigh en all humb screws.
WARNIN
Hazardous Voltage: DO NOT remove he ape from he back of he
windows ha are no used, as his main ains he Touch-Safe
fea ure.
MAX PAC I
L2
L1 X1
Single Phase
Resisti e
L2 Connection is
NOT on MaxPac

- 13 -
© 2002 Chromalox®, Inc.1-888-996-9258
MaxPac II
MaxPac III
Three Wire
2 Leg Control
MAX PAC II
L1
L3
L2
X1
X3
L2 Connection is
NOT on MaxPac
Four Wire
3 Leg Control
MAX PAC III
L1
L2
L3
X1
X2
X3
N
N Connection is
NOT on MaxPac
IMPORTANT: The I2 fuses ins alled on he SCR are designed o pro ec he SCR
from faul s on he load connec ion side. They are NOT in ended o provide wire
pro ec ion.
CAUTION

- 14 - © 2002 Chromalox®, Inc. 1-888-996-9258
MaxPac III
MaxPac IP
IMPORTANT: The I2 fuses ins alled on he SCR are designed o pro ec he SCR
from faul s on he load connec ion side. They are NOT in ended o provide wire
pro ec ion.
CAUTION
Three Wire
3 Leg Control
MAX PAC III
L1
L2
L3
X1
X2
X3
Single Phase
transformer
Coupled
MAX PAC IP
L2
L2
L1 X1
L2 connection to
MaxPac is instrument
power only

- 15 -
© 2002 Chromalox®, Inc.1-888-996-9258
The bus bars are designed o accep NEMA s andard wo-hole crimp lugs in accordance wi h he char s below.
The following drawings show proper ins alla ion of he crimp lugs on he bus bars:
Illustration 1: View From Rear Ven ila ed Panel
F
U
S
E
LINE BUS BAR
LOAD BUS BAR
FAN END
SCR
Illustration 2: View From Top
Touch-Safe Units
100 - 400 Amps
Inpu Bus
Up o (3) 1/0 - 300 mcm (70 mm2 — 150 mm2)
Up o (2) 350 - 500 mcm (185 mm2 — 240 mm2)
Ou pu Bus
Up o (10) #8 - #1 (10 mm2 — 50 mm2)
Up o (3) 1/0 - 300 mcm (70 mm2 — 150 mm2)
Up o (2) 350 - 500 mcm (185 mm2 — 240 mm2)
550 - 650 Amps
Inpu Bus
Up o (4) 1/0 - 300 mcm (70 mm2 — 150 mm2)
Up o (3) 350 - 500 mcm (185 mm2 — 240 mm2)
Ou pu Bus
Up o (12) #8 - #1 (10 mm2 — 50 mm2)
Up o (4) 1/0 - 300 mcm (70 mm2 — 150 mm2)
Up o (3) 350 - 500 mcm (185 mm2 — 240 mm2)
800 - 1200 Amps Open Design
Inpu and ou pu bus drilled o accomoda e q y (4) 1/0 - 500 mcm NEMA s andard wo-hole crimp lugs per phase.

- 16 - © 2002 Chromalox®, Inc. 1-888-996-9258
The power wires mus always connec o he fuse side (refer o illus ra ion 1 on page 15) of he bus bar. This
is essen ial o main ain he required spacing be ween he phases and sides, and o align wi h he openings in
he op. The only excep ion o his is when using power dis ribu ion using connec ors of sizes #8 o #1. There
is adequa e spacing for hese connec ors o be moun ed on bo h sides of he bus bar, if necessary.
The bolt head should always be on he ou side of he bus bar (refer o illus ra ion 2 on page 15) wi h he bol
ex ending owards he fuse.
Flat washers should be used on bo h he bol head and he nu , and a lock-washer should be under he nu .
The Touch-Safe MaxPac is designed o allow bo h inpu and ou pu wiring o en er/exi in ei her direc ion. On
he 550 Amp and 650 Amp models, i is necessary o moun he wire in he holes ha maximize he dis ance
for he wire o exi he enclosure. This maximizes he dis ance from he cover o he non-insula ed connec or.
When using he power distribution fea ure and moun ing erminals on bo h sides of he bus bar, he wires
moun ed on he ou side of he bus bar mus be ben inward sligh ly o align wi h he opening in he op. All
wiring, especially he larger wires, should be ben prior o moun ing o he bus bars. DO NOT use he bus bars
as an anchor o bend he power cables.
4.2.4 - Instrument Power
MaxPac requires 120 or 230 Vac 50/60Hz for instrument power. This voltage supplies power for the
control circuits, fans, high temperature warning indicator, and shorted SCR Indicators (see Fig. 1 on
page 21).
This supply is fused on the main circuit board.
4.2.5 - rounding
Chasis is provided wi h hole pa ern for s andard NEMA wo-hole crimp lugs.
WARNIN
Hazardous Voltage: This Elec rical Equipmen mus be ins alled by
a qualified person and effec ively grounded in accordance o he
Na ional Elec ric Code and local codes.
IMPORTANT

- 17 -
© 2002 Chromalox®, Inc.1-888-996-9258
4.2.6 - Command Signal Wiring
Please refer o he figures on page 19 for illus ra ions of he 6-, 8-, and 10-pin inpu erminals.
MaxPac I, II, and III
On/Off Control Signals
AC Input – The 120 hru 230 Vac signal lines are connec ed o erminal J1 - 7 & 8 (see Fig. 9 on
page 21). An inpu vol age of 120 o 230 Vac urns he power On. The urn OFF vol age is 0 Vac.
DC Input – The 5 - 32 Vdc signal lines are connec ed o erminal J3 - 1 & 4 (see Fig. 10 on page 21).
An inpu vol age of 5 o 32 Vdc urns he power On. The urn OFF vol age is 0 Vdc.
Contact Closure Input – The dry con ac signal lines are connec ed o erminal J3 - 1 & 2 (see Fig. 11
on page 21). A closed con ac urns he power On. The urn OFF vol age is an open con ac .
Process Analog Control Signals
MaxPac I, II, and III have been fac ory calibra ed. These uni s accep 0 - 5, 1 - 5, 0 - 10 Vdc, and 4 - 20
mA inpu signals ha are connec ed o Terminal Block J2. The following signals are connec ed o:
0 - 5 Vdc: Terminal J2 - 9(+) & 7(-) (see Fig. 7 on page 21)
1 - 5 Vdc: Terminal J2 - 5(+) & 7(-) (see Fig. 5 on page 21)
0 - 10 Vdc: Terminal J2 - 10(+) & 7(-) (see Fig. 8 on page 21)
4 - 20 mA: Terminal J2 - 6(+) & 7(-) (see Fig. 6 on page 21)
Auto/Manual Input
The MaxPac I, II, and III can be
wired o make i possible o
selec an inpu from ei her a
empera ure process con roller
or a manual inpu po en iome er.
A swi ch is used o selec
be ween he inpu from a 1K
po en iome er and a linear
con rol inpu (see Fig. 4 on page
21). The uni is shipped wi h a
jumper from erminals 2 and 3 of
erminal block J2 (see illus ra-
ion 3). Remove jumper o ins all
au o/manual inpu .
Demand Indicator
The LED demand indica or is loca ed on he main PC board and is viewable hrough he cover. Wi h he
On/Off con rol op ion, he indica or will display s eady “on” and s eady “off”. Wi h he DOT Firing op ion,
he indica or will display he rapid firing sequence.
IMPORTANT: When enabling he Au o/Manual Inpu , he jumper from erminals 2
and 3 of erminal block J2 mus be removed.
CAUTION
Illustration 3
N
C
N
O
CO
NTA
CT
N
O
RMALLY
C
L
OS
E
D
(
SWNC
)
CO
NTA
CT
N
O
RMALLY
O
PE
N
(
SWN
O)
S
WIT
C
H
A
SS
EMBLY
(
SW
)
PANEL T
O
B
E
MOU
NTED T
O
LE
G
EN
D
PLATE
(
LP
)
A
U
T
O
HAND
S
WIT
C
H KN
OB
(
SW
)
A
U
T
O
HAND
WIRIN
G
1
4
N
C
N
O
1K
P
O
TENTI
O
METE
R
J2
CW
2
3

- 18 - © 2002 Chromalox®, Inc. 1-888-996-9258
SCR Control Board
The Basic con rol board provides he following func ions:
The low vol age dc o opera e he circui ry:
A swi ching regula or circui conver s he ins rumen power vol age o +12Vdc.
The power dis ribu ion for he cooling fans:
The incoming ins rumen power is fused and hen rou ed o he fan power erminals.
The signal condi ion for he on/off inpu and analog inpu s:
The 120 o 240 on/off inpu is isola ed by an op o-coupler. The dc and con ac closure inpu s are
buffered by he circui ry. Amplifiers conver he analog inpu s and he po en iome er inpu o a
signal level compa ible wi h he op ional propor ional firing board. The plug-in recep acle for he
op ional propor ional board allows for an easy upgrade o propor ional con rol.
The drive signal o he SCR rigger boards:
The empera ure alarm:
The hea sink empera ure is derived from a solid s a e sensor moun ed on he
hea sink. This is hen compared o wo se poin s. The firs alarm is a warning and
ac iva es he ex ernally connec ed device. This allows ime o correc he problem
before he second alarm inhibi s he firing circui .
The Shor ed SCR Alarm:
The plug-in recep acle for he shor ed SCR board is loca ed on his board. Signals from
he SCR are rou ed o he op ion board. When a shor is de ec ed he ex ernally
connec ed device ou pu is ac iva ed.
2AMP (2AG)
CHROMALOX P/N 0024-01097
LITTLEFUSE P/N 225 002

- 19 -
© 2002 Chromalox®, Inc.1-888-996-9258
Proportional DOT Firing Board
Chromalox’s exclusive DOT (De-
mand Orien ed Transfer) firing
echnique swi ches he fewes
number of cycles o provide he
mos precise zero crossover con rol.
A 50% ou pu , he uni ’s ou pu
al erna es be ween one cycle “On”
and one cycle “Off.” A 51%, he
ou pu con inues wi h one cycle
“On,” one cycle “Off,” and gradually
in egra es one ex ra “On” cycle for
he addi ional 1%.
Remote Shutdown
When i is necessary o disable he ou pu , connec a dry con ac be ween J3 - 3 & 4 (see Fig. 12 on
page 21). When i is closed, he power con rol will shu OFF.
Shorted SCR Detection (optional)
This op ion provides a means of aler ing an opera or o a problem wi h he sys em. An ex ernal
indica ing lamp or relay can be connec ed o J1 - 5 & 6 (see Fig. 2 on page 21). This indica or mus
be ra ed for he ins rumen power applied o J1 - 1 & 2. Three diagnos ic LEDs show which SCR pair
is faul ed. These ligh s are synchronized wi h he demand indica or and can only indica e while he
demand is ac ive. Shor ing J3 - 5 & 6 can disable he ou pu a J1 - 5 & 6. The alarm can be selec ed
as la ching or non-la ching.
A la ching alarm means ha if he alarm ac iva es and he sys em subsequen ly re urns o normal, he
alarm will remain la ched un il a rese bu on (ex ernal swi ch – cus omer provided) is pressed. A non-
la ching alarm rese s au oma ically.
IMPORTANT: This shu down overrides he con rol inpu only. I will NOT pro ec agains
faul ed or damaged SCRs.
CAUTION
SHORTED SCR DETECTION
DEMAND
123
SHORT J3-1 & 2 FOR
1 CYCLE FIRING
SHORT J3-2 & 3 FOR
3 CYCLE FIRING
Uni shipped for 3 cycle opera ion