Chromalox MaxPac User manual

PK480-5
0037-75428
June 2018
User’s Manual
MaxPac

1
Thank you for choosing the Chromalox®MaxPac™ - a complete power control solution with industry-best
price and performance.
For more than 100 years, customers have relied on Chromalox for the utmost in quality and innovative solu-
tions for industrial heating applications. Chromalox manufactures the world’s largest and broadest line of
electric heat and control products.
The MaxPac Series SCR Controllers provide the best control for applications where consistent heater/pro-
cess temperature is critical or where fine resolution of power is required.
Common MaxPac features include:
• 120 - 575 Vac @ 100 - 1200 Amps
• Isolated Control Circuit
• Flexible I/O Power Wiring
• Easy Customer Interface
• Remote Stop
• Compact Size and Construction
• Touch-Safe Design (option on 100 - 650 Amp models)
• dv/dt Transient Voltage Protection
• MOV Protection
• Built-In Power Distribution
• Soft Start
• 100KA SCCR Rating
Features for the MaxPac I, II, and III include:
• Zero Crossover Firing
• Isolated Control Circuit
On/Off Control Inputs:
120 thru 240 Vac
5 - 32 Vdc
Dry Contact Closure
Proportional (DOT Firing) Inputs:
4 - 20 mA, 0 - 20 mA, 0-5 Vdc, 1 - 5 Vdc, 0 - 10 Vdc
Remote Manual Adjust (Optional)
Remote Auto/Manual Switch (Optional)
• Electronically Protected with Temperature Warning and Stop System
• Cycle Resolution 3, 5, 7, 11, 13, 17, 19
• Shorted SCR Detection (Optional)
• Soft Start
• Time proportional switching mode
• Staged Heating
• Rotary wwitch selection of input, leg configuration, modbus
Features for the MaxPac IP include:
• Phase Angle Firing
• Isolated Control Circuit Inputs
0 - 5 mA, 0 - 20 mA
0 - 50 mA, 1 - 5 mA
4 - 20 mA, 10 - 50 mA
0 - 5 Vdc, 0 - 10 Vdc
• Optional Current Limit
• Soft Start
• Line Voltage Compensation
• Zero & Gain Adjustments
• Built-In Manual Adjustment
• Current Limit Adjustment (Optional)

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Table of Contents
Section Topic Page
1................................................. Important Safeguards..................................................................................... 3
2................................................. Description ..................................................................................................... 4
3................................................. Before You Install............................................................................................ 5
4................................................. Installation ...................................................................................................... 6
4.1................................. Mounting......................................................................................................... 8
4.2................................. Wiring............................................................................................................ 11
4.2.1 ............. Touch-Safe Design ....................................................................................... 11
4.2.2 ............. Cover Removal and Installation.................................................................... 12
4.2.3 ............. Power/Load Wiring....................................................................................... 12
4.2.4 ............. Instrument Power ......................................................................................... 16
4.2.5 ............. Grounding..................................................................................................... 16
4.2.6 ............. Command Signal Wiring............................................................................... 17
4.2.7 ............. Calibration .................................................................................................... 23
5................................................ Specifications ............................................................................................... 24
6................................................ Maintenance ................................................................................................. 25
7................................................ Troubleshooting ............................................................................................ 26
8................................................ Parts and Accessories.................................................................................. 27
9................................................ Warranty and Return Information ................................................................. 28
10 .............................................. EC Declaration of Conformity....................................................................... 37

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1
Please read all instructions before installing and operating your MaxPac™.
Before working inside the equipment, confirm that all power has been turned off, locked off, and pref-
erably earthed [grounded] at all points of low and high potential, on both the supply line and load side
circuits, as required / permitted by all codes and standards.
Personnel working with or near high voltages should be familiar with modern methods of resuscitation. Con-
tact an area supervisor or safety personnel for more information.
Throughout the MaxPac User Manual, the safety alert and the international electric shock/electrocution
symbols will alert you to potential hazards. Safety precautions should always be followed to reduce the risk
of personal injury to persons from fire and electrical shock hazards.
Each safety message is preceded by a safety alert symbol and one of three words: DANGER, WARNING, or
CAUTION. These mean:
DANGER You WILL be killed or seriously hurt if you do not follow instructions.
WARNING You CAN be killed or seriously hurt if you do not follow instructions
CAUTION You CAN be hurt if you do not follow instructions.
Important Safeguards
Damage Prevention Messages:
You will see other IMPORTANT messages that are proceeded by the word CAUTION that are intended
to help prevent damage to the MaxPac™ or other equipment. Note that Damage Prevention Messages are
NOT accompanied by the Safety Alert Symbol.
Key Safety Practices
All personnel working on high voltage electrical equipment must adhere to all national and local regulations,
codes, and standards.
Only suitably qualified and experienced persons, who are familiar with this equipment, and the work they are
to do, should carry out installation, commissioning, operation, or maintenance of this panel and the associ-
ated heater.
Such persons shall adhere to proper high voltage safety procedures, including the use of appropriate per-
sonal protective equipment (ppe).
Failure to adhere to any of the above may result in equipment damage, operating losses, injury, or death.
Chromalox will not be liable for failure to adhere to all governing regulations, codes, standards, site proce-
dures and information given in this manual.
The MaxPac User Manual uses this symbol to
alert personnel to potential hazards that may
damage the equipment.
The MaxPac User Manual uses this symbol to
alert personnel to potential hazards that may
cause injury or death.
IMPORTANT SAFEGUARDS

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2
† This can be set to three cycles ‘On’ / three cycles ‘Off’ (see section on installation options).
Description
MaxPac I, II, and III
The Chromalox Model MaxPac IP, I, II and III Series are specifically designed for the OEM market. The Chro-
malox MaxPac I, II and III controllers are highly versatile SCR Power Paks. Firing modes includes On/Off
and DOT proportional zero voltage switching. Chromalox’s exclusive DOT (Demand Oriented Transfer) firing
switches the fewest number of cycles to provide the most precise zero crossover control. At 50% output the
units output alternates between one cycle “On” and one cycle “Off”. At 51% the output continues with one
cycle “On” one cycle “Off” and gradually integrates one extra “On” cycle for the additional one percent. This
DOT fired technique also minimizes temperature overshoot, temperature fluctuations and helps extend the
loads element life due to reduced thermal shock.
The power SCR assemblies consist of one, two or three SCR’s connected back to back with a semiconductor
fuse, RC Snubber and MOV protection. The firing circuit is based on common integrated circuit. Diagnostic
indicators are included as well as plug-in terminal blocks for easy customer interface.
MaxPac IP
The Chromalox MaxPac IP utilizes Single Phase, Phase Angle firing to modulate power to an inductive or
resistive load. Phase Angle control has the advantage of proportioning every cycle thereby providing very
fine resolution of power. Fast responding loads in which the resistance changes as a function of temperature
require Phase Angle control. The MaxPac IP offers a Soft Start feature that assures that the load power is
gradually increased from zero to the value set by the command signal in the event of a power interruption.
In addition, optional Current Limit is used to protect the load, SCR controller and the total system from large
surge currents that could occur at start-up.

5
3
Before You Install
Immediately after receiving your MaxPac I, II, III or IP Series Controller, visually inspect the shipment packag-
ing and record any damage on the shipping documents. Unpack the controller and carefully inspect for obvi-
ous damage due to shipment. If any damage has occurred, YOU must file a claim with the carrier company,
since the carrier company will not accept a claim from the shipper (Chromalox).
Be sure to check the model number and verify that you have received the correct Model of controller.
If the controller is not installed and placed into operation immediately, it should be stored in a cool, dry envi-
ronment. Temperature extremes and excessive moisture can damage the controller.
Before choosing a location in which to mount your MaxPac, please consider the following:
Temperature
When mounting the SCR unit in a control panel, attention should be paid to the enclosure tempera-
ture. The SCR is rated to perform at its nameplate current rating in temperatures up to 50˚C (122˚F).
Ensure that adequate ventilation is provided or some other method of maintaining the correct cabi-
net temperature is used.
Cleanliness
Careful attention must be paid in areas subjected to airborne particles. The efficiency of the heat
sinks relies on their conducting surfaces being maintained in a clean manner. (See the Maintenance
Section.)
Dampness
High humidity or hosing down a unit should be avoided.
Clearance
Choose a location that will provide adequate spacing around the unit when mounted. This will en-
sure proper air flow necessary to cool the device.
WARNING
Hazardous Voltage: Disconnect and lockout power before in-
stalling or servicing. Failure to comply could result in per-
sonal injury or equipment damage.
READ AND UNDERSTAND BEFORE
CARRYING OUT THE WORK DETAILED BELOW

6
Installation
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
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 Max-
Pac 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 de-
signs allow incoming and outgoing wiring in either
direction.

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Examples of Proper Air Flow
Pagoda Top
Fan
Air
Louvers
Louvers
MaxPac
Air
Fan MaxPac
Fan
Enclosure
Air
Enclosure
Fan
Filter
Forced Air In
(Recommended)
Forced Air Out
(Not Recommended)
Louvers
Since hot air rises naturally, it is not recommended that cooling air enter from the top and exhaust at the bot-
tom of the enclosure.

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4
Installation
Please read all information in this section before beginning the installation of your MaxPac.
Installation of the MaxPac requires three steps:
1. Mounting
2. Power wiring
3. 120 or 230 VAC 50/60hz for instrument power. See 4.2.4, pg. 16.
4.1 - Step 1: Mounting
Before mounting your MaxPac, please read the section titled “Before You Install’ on page 5 for a description
of an ideal environment for the unit’s operation.
The space required for mounting the MaxPac Power Pak depends upon the model. The table below refers to
the figures on the following pages. These figures illustrate the dimensions and mounting holes for the vari-
ous MaxPac Power Pak models. Please refer to these figures before mounting your unit.
Figure 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 units, consult factory
IMPORTANT: Please note that the figures on the following pages are
not drawn to the same scale.
READ AND UNDERSTAND BEFORE
CARRYING OUT THE WORK DETAILED BELOW