Ametek ZF1 SCR Series Operation and maintenance manual

SCR POWER CONTROLLER
Instruction, Operation and
Maintenance Manual
Number: 9100037
Revision 3
530 Lakeview Plaza Blvd, Ste C
Worthington, Ohio, USA 43085
Toll F re e : 1 - 8 88- PWR- C NTL (7 9 7 -26 85)
Ph o n e: 61 4 -3 0 8-550 0
Fa x : 614 - 3 08 - 5506
Web: w w w .hd rpow e r. c o m
ZF1 SCR Series
60-1200 Amperes
Single-phase
Zero-fired

This manual applies to all Model ZF1 SCR Power Controls. Former ZF1 manual – 9100029 has been replaced
with this manual.
For the support representative nearest you, please call Ametek HDR Power Systems main office at (614)-308-
5500.
Revision 1 September 2014 Initial Release
Revision 2 July 2015 Revised Address
Revision 3 Aug 2022 General Revision
 2022 by Ametek HDR Power Systems. No portion of this document may be reproduced either mechanically or electronically without the
prior consent of Ametek HDR Power Systems.

ZF1 SCR Power Controller Table of Contents
Rev 3 Ametek HDR Power Systems i
TABLE OF CONTENTS
IMPORTANT SAFETY INSTRUCTIONS ............................................................................................................. 1
CHAPTER 1 - DESCRIPTION .............................................................................................................................. 3
1.1 General Description 3
1.2 Application 3
1.3 Operation 3
1.4 Specification 3
CHAPTER 2 - OPTIONS ...................................................................................................................................... 5
2.1 Option LG (Lug Kit) 5
2.2 Additional Options 5
CHAPTER 3 - INSTALLATION ............................................................................................................................ 7
3.1 Mounting the ZF1 7
3.2 Input/Output Wiring 7
3.3 Fan Wiring (applicable to models rated 90 A and higher) 7
3.4 Wiring Overtemperature Contacts 8
3.5 Command Signal Input 8
3.6 Voltage Changeover 9
CHAPTER 4 - OPERATION ............................................................................................................................... 11
4.1 General 11
4.2 Front Panel Indicators 11
4.3 Command Input Control 11
4.4 Remote Manual Control with a Potentiometer 12
4.5 Auto/Manual Control with a Controller and Remote Potentiometer 13
4.6 On/Off Control 14
4.7 Shutdown 14
CHAPTER 5 - THEORY...................................................................................................................................... 15
5.1 Functional Description 15
5.2 Digital Firing Control Circuit 15
5.3 Variable-Time Base 15
5.4 Pulse-Train Firing 16
5.5 Phase-Lock Loop 16
5.6 SPAN and ZERO Controls 16
5.7 Voltage-Squared Feedback 16
5.8 Shut-down 16
CHAPTER 6 – TROUBLESHOOTING ............................................................................................................... 17
6.1 Customer-Service Program 17
6.2 Troubleshooting Typical Symptoms 17
6.3 Static Precautions when Servicing 17
6.4 Environmental Problems 18
6.5 Input Power and Load Connections 18
6.6 Correcting Troubles in the ZF1 Itself 19
CHAPTER 7 - SERVICE ..................................................................................................................................... 21
7.1 Communication Procedures 21
7.2 Spare Parts Orders – Routine or Emergency 21
7.3 Spare Parts List 22
7.4 Drawing List 23

Table of Contents ZF1 SCR Power Controller
ii Ametek HDR Power Systems Rev 3
CHAPTER 8 – WARRANTY POLICY ................................................................................................................ 25
8.1 Warranty 25
8.2 In-house Repair Services 25
APPENDIX .......................................................................................................................................................... 27
Appendix A – ZF1 System Schematic 27
Appendix B – ZF1 60-225 A Outline 28
Appendix C – ZF1 350-500 A Outline 29
Appendix D – ZF1 650 A Outline 30
Appendix E – ZF1 800-1200 A Outline 31
Appendix F – Declaration of Conformity 32

ZF1 SCR Power Controller Table of Contents
Rev 3 Ametek HDR Power Systems iii
TABLE OF CONTENTS
Par. Title Page
ILLUSTRATIONS
Figure 3.1 Fan and Thermostat Connections .................................................................................................. 8
Figure 3.2 Isolated/Non-Isolated Switches ...................................................................................................... 9
Figure 3.3 T1 Transformer Connections .......................................................................................................... 9
Figure 3.4 Typical ZF1 Line and Load Connections ..................................................................................... 10
Figure 4.1 Control Panel .................................................................................................................................. 11
Figure 4.2 Process Controller Input Connections ........................................................................................ 12
Figure 4.3 Remote Control with a Potentiometer ......................................................................................... 13
Figure 4.4 Auto/Man Control with Controller and Remote Potentiometer ................................................. 13
Figure 4.5 On/Off Control ................................................................................................................................ 14
Figure 4.6 Shutdown Control .......................................................................................................................... 14
Figure 5.1 AC Switch ....................................................................................................................................... 15
TABLES
Table 1.1 ZF1 Model Number Breakdown ........................................................................................................ 3
Table 1.2 General Specifications of ZF1 Models ............................................................................................ 4
Table 3.1 Wire Size Information ........................................................................................................................ 7
Table 3.2 Transformer Voltage Wiring ........................................................................................................... 10
Table 5.1 Variable-Time-Base Relationship (Example) ................................................................................ 15
Table 6.1 Troubleshooting Chart (Symptoms and Solutions) ..................................................................... 19
Table 6.2 Torque Specifications ..................................................................................................................... 19
Table 7.1 ZF1 Spare Parts List ........................................................................................................................ 22
Table 7.2 ZF3 Drawing List .............................................................................................................................. 23

Table of Contents ZF1 SCR Power Controller
iv Ametek HDR Power Systems Rev 3

ZF1 SCR Power Controller Safety Instructions
Rev 3 Ametek HDR Power Systems 1
SAVE THESE INSTRUCTIONS
IMPORTANT SAFETY INSTRUCTIONS
WARNING
Observe all warnings and cautions in this manual. Failure to do so may result in serious injury or death.
Refer all service to properly trained and qualified service personnel. Never work alone.
Lethal voltages exist on exposed heat sinks even if the power controller is turned off. Remove power and lock
out power before attempting any service.
This manual contains important safety instructions that must be followed during the installation and
maintenance of the SCR Power controller. Read this manual thoroughly before attempting to operate this
Power controller.
An appropriate branch circuit fused disconnect or circuit breaker with this Power Controller is required to
ensure the safety of operating personnel.
CAUTION
HAZARDOUS VOLTAGES exist at the Power Controller Heat Sinks and at the Load, AT ALL TIMES, when
input voltage is connected. This condition exists even when the Power Controller is set to deliver zero output.
Printed circuit boards contain sensitive components that can be damaged by electrostatic discharge (ESD).
Observe precautions for handling electrostatic sensitive devices. Reference Maintenance and Troubleshooting
(Chapter 6) of this manual for details
In case of fire, use a dry chemical fire extinguisher to put out the fire. Using a liquid fire extinguisher may
cause electric shock.
The SCR Power Controller makes use of components dangerous for the environment (electronic printed circuit
boards, electronic components). The components removed must be taken to specialized collection and
disposal centers.
E151547
100kA SCCR
IEC 947-5-1

Safety Instructions ZF1 SCR Power Controller
2 Ametek HDR Power Systems Rev 3

ZF1 SCR Power Controller Description
Rev 3 Ametek HDR Power Systems 3
CHAPTER 1 - Description
1.1 General Description
The ZF1 is Single-phase SCR Power Controller. Each of these can operate with a wide variety of
input signals and line voltages up to 575 Vac and currents ranging from 60 through 1200 amperes.
The ZF1’s output voltage is proportional to its input signal. HDR’s zero-fired SCR Power Controls
utilize a variable-time-base that helps maintain constant power to the load. This variable-time-base
also helps minimize temperature overshoot, temperature fluctuations and helps extend the load
element’s life due to reduced thermal shock. The ZF1 also features pulse-train firing which provides
high immunity to possible SCR firing disturbances, and phase-lock loop circuitry which ensures line
frequency synchronization. Other features are input isolation from ground, soft-start, and automatic
restart circuitry. Terminals are provided to permit connection of a variety of external control methods.
1.2 Application
Zero-Fired SCR Power Controls provide control of single-phase power by the switching action of two
SCRs connected back to back. By switching at the zero crossing point, RFI (Radio Frequency
Interference) is virtually eliminated. Zero-Fired controllers are versatile enough to be used in place of
mechanical contactors and mercury relays on dryers, kilns, ovens, environmental chambers,
extruders, and most other applications where resistive heating elements are used. Normal Zero-Fired
SCR Power Controllers should never be used on inductive loads.
1.3 Operation
The ZF1 accomplishes power control by the switching action of a pair of inverse-parallel power SCRs.
The switching, or gating, of the SCRs is controlled by a digital firing control circuit synchronized “in
phase” with line frequency (either 50 or 60 Hz). The output may be adjusted by the on-board multi-
turn potentiometers or by a voltage or current signal from a process controller. ZERO and SPAN
controls allow the user to calibrate the SCR unit's output to the process command signal. Terminals
are available for connection of a remote manual potentiometer.
1.4 Specification
Specifications for the ZF1 SCR power controller are given in Tables 1.1 and 1.2.
Table 1.1 ZF1 Model Number Breakdown
ZF1 – 480 – 225 – CR – UB – 01
NOTE: N.O. Thermostat is included in current ratings above 60 A.
120 Vac - 120
240 Vac - 240
400 Vac - 400
480 Vac - 480
575 Vac -
575
60 A rms - 60
90 A rms - 90
120 A rms - 120
180 A rms - 180
225 A rms - 225
350 A rms - 350
500 A rms - 500
650 A rms - 650
800 A rms - 800
1000 A rms - 1000
1200 A rms
-
1200
N.O. Thermostat - NO
N.C. Thermostat - NC
Lug Kit (>225 A) - LG
Can have multiple selections
4-20 mA - 01
0-10 Vdc - 02
0-5 Vdc - 03
Auto/Man - 04
Manual Pot input - 05
Others
-
xx

Description ZF1 SCR Power Controller
4 Ametek HDR Power Systems Rev 3
Table 1.2 General Specifications of ZF1 Models
Input line voltage: * 120, 240, 400, 480, or 575 Vac,
+10%, -15% , Single-phase
Line frequency: * 50 or 60 Hz
Current rating:
*
As indicated by model number (refer to Table 1.1)
Thermostat contact rating: 120 Vac, 5 A; resistive
Input Signal:
Non-isolated
Isolated
0 to 1.5 V (min); 0 to 10 V (max)
0 to 6 mA (min); 0 to 20 mA (max)
Control methods: 1. Potentiometer, 5 kΩ, 1/2 watt (Customer-supplied).
2. Dry contact closure (customer-supplied).
3. Temperature or process controller
*
*
Control signal input impedance:
Non-isolated input
Isolated input
1500 Ω
500 Ω
Control signal isolati
on:
From SCRs 2,500 Vac
From ac power input lines 2,500 Vac
From chassis 500 Vac
Power output:
Power output linearity versus
control signals input
+3%
Power SCRs protection:
Current surge Subcycle I² T semiconductor fuse.
Transient voltage spikes (dv/dt) Metal Oxide Varistor (MOV) and R-C snubber across each SCR pair; all
SCRs have PIV rating of 1,400 V.
SCCR Rating 100kA
Miscellaneous:
Zero-firing timebase Variable see 5.3
Controls: ZERO and SPAN potentiometers; 10-turn, screwdriver-adjustable.
Approvals UL/cUL (E151547), CE
Fan
-
cooling power (as applicable):
For 90 A through 500 A units 0.21 amperes, 25 VA (50 Hz)
0.19 amperes, 23 VA (60 Hz)
For 650 A through 1200 A units 1.2 amperes, 144 VA (50 Hz)
1.4 amperes, 168 VA (60 Hz)
Ambient T
emperature range:
Environment 32 ºF to 122 ºF ( 0 ºC to 50 ºC) surrounding air
Pollution degree 2
Overvoltage Category III
Storage 14 ºF to 158 º F ( -10 ºC to 70 ºC)
Weight per unit
Current Rating
l
bs
kg
60 through 225 A
350, 500 A
650 A
800, 1000, 1200 A
22
24
27
71
10
10.9
12.3
32.2
Outline and mounting: See appropriate drawing in Appendix
* Specify with order
** If you will be using temperature/process controller, specify its output; e.g., 4-20 mA, 0-10 Vdc, 2-10 Vdc,
etc. with your order.
NOTE: The ZF1 should be tested or operated with an adequate load since an open output will have line
voltage at the load connections.

ZF1 SCR Power Controller Options
Rev 3 Ametek HDR Power Systems 5
CHAPTER 2 - Options
2.1 Option LG (Lug Kit)
Option LG will provide compression lugs for the 350-1200 A Power Controllers.
2.2 Additional Options
The options described above are the ones most commonly used. Additional options are available. For
more information, contact Ametek HDR Power Systems.

Options ZF1 SCR Power Controller
6 Ametek HDR Power Systems Rev 3

ZF1 SCR Power Controller Installation
Rev 3 Ametek HDR Power Systems 7
CHAPTER 3 - Installation
3.1 Mounting the ZF1
Determine the voltage and current ratings from the nameplate of the unit (refer to Table 1.1). Then
determine space and mounting hole requirements by referring to the outline drawing (at the Appendix)
that applies to your model’s current rating. Mount the unit so the line and load connections are at the
top and ensure that upward airflow over the heat sink fins is unrestricted. On high current models,
allow adequate clearance for routing the relatively large diameter input and output lines.
3.2 Input/Output Wiring
Using appropriately sized and insulated conductors for the voltage and current ratings of your model,
make connections as shown in Figure 3.4 (Refer to Table 3.1 for wire size information). Torque
specifications of bolted connections can be found in Table 6.2.
A ground wire is required for proper operation. Use a 10 AWG or larger wire.
NOTICE
Use copper conductors rated 75 ºC minimum for all model current ratings.
The fuses included are NOT meant for over current protection, separate branch circuit protection is
required.
On the “internal” side of the ZF1, the wire from L2 should connect to the appropriate tap of transformer
T1, depending on the line voltage to be used. Check the T1 connection by opening the ZF1 cover; T1
terminal voltages are clearly marked. Reference Chapter 3.6.
Table 3.1 Wire Size Information
Model Size Wire/Cable
60 A 8 to 0 AWG
90 A 8 to 0 AWG
120 A 8 to 0 AWG
180 A 6 to 250 MCM
225 A 6 to 250 MCM
3.3 Fan Wiring (applicable to models rated 90 A and higher)
ZF1 models rated 90 A and higher with cooling fans require 120 Vac power which must be supplied by
the customer. Fan power should be connected to terminals 21 and 22 as shown in Figure 3.1. Refer
to Table 1.2 for fan power requirements by model.
The ZF1 terminals available for the 120 Vac fan connections are shown Figure 3.1 and in the
schematic in Appendix A. Optional 220 Vac fans are available.
WARNING
Branch circuit overcurrent protection required is to be provided in
accordance with the national and local codes of the inspecting authority.

Installation ZF1 SCR Power Controller
8 Ametek HDR Power Systems Rev 3
3.4 Wiring Overtemperature Contacts
Normally-open (N.O.) heat sink thermostats are standard on all fan-cooled models (rated 90 A and
higher). These thermostats, which close on high heat sink temperature (200 ºF), may be used to
initiate an alarm, shunt trip, or other device for SCR protection. Thermostat connections are on
terminals 23 and 24 as shown in Figure 3.1.
If desired, normally-closed (N.C.) contacts may be substituted for the normally-open (standard). Heat
sink thermostats are optional on units with current ratings lower than 90 amperes and can be ordered
with either N.O. or N.C. contacts.
FAN POWER
120 Vac
(220 Vac
OPTIONAL)
OVER TEMP
N.O. STANDARD
(N.C. OPTIONAL)
21 22 23 24
Figure 3.1 Fan and Thermostat Connections
3.5 Command Signal Input
HDR’s Zero-Fired SCR Power Controllers have the capability of having either an isolated current or
non-isolated voltage Command Signal input. The standard input impedance is 500 ohms for isolated
and 1500 ohms for non-isolated.
All units are equipped with DIP switches, select “isolated” position for a 4-20 mA command signal and
“non-isolated” for a voltage input such as 0-10 Vdc. See Figure 3.2.
The isolated input works best with an offset Command Signal such as 4-20 mA; however, it will work
with both offset and zero based Command Signals. Zero based Command Signals may have a small
amount of non-linearity (input to output) at the low end. This should not be a problem on closed loop
systems.
CAUTION
The application of fan power should precede, or coincide with, the turn-on of
the line voltage source that is to be controlled by the disconnect. How this is
accomplished and en
sured is up to the
customer.

ZF1 SCR Power Controller Installation
Rev 3 Ametek HDR Power Systems 9
----OPEN ----
1234C1
C2
1
2
NON-ISOLATED-C2
SW2
ISOLATED-C1
SW1
Current Input Voltage / Manual Pot Input
Figure 3.2 Isolated/Non-Isolated Switches
3.6 Voltage Changeover
On occasion, customers may wish to operate a ZF1 SCR Power Controller on line voltages other than
what was specified when originally ordered. The ZF1 may be changed to accept a wide range of line
voltages (120, 240, 400, 480, 575 Vac), so long as the load current does not exceed the ZF1’s current
rating. This is accomplished by performing the procedure described below.
.
Using the system schematic (located in the Appendix) as reference, perform the voltage changeover
procedure as follows.
1. Open the SCR power controller, and locate transformer T1. The primary side of T1 transformer
will contain two wires (one black, the other white and black). Refer to figure 3.3.
Figure 3.3 T1 Transformer Connections
2. Unsolder the Black/White wire on T1 from the voltage tap, and resolder it to the tap desired, as
shown in Table 1. Route the wires so that they are physically located under the transformer
terminals
WARNING
Voltage changeover should be performed by qualified personnel only.
Always remove power and properly lock out power to the unit before
attempting any service.
LED
SPAN
1.5K
----OPEN ----
1234C1
C2
1
2
NON-ISOLATED-C2
SW2
ISOLATED-C1
SW1
NA

Installation ZF1 SCR Power Controller
10 Ametek HDR Power Systems Rev 3
Table 3.2 Transformer Voltage Wiring
Desired Voltage T1 White &
Black Wire to
120 120
208 240
220 240
240 240
380 400
400 400
415 400
480 480
575 575
3. Close the unit, and apply line power. The unit is now ready for operation on the line voltage
selected. It is a good idea to identify the unit with a label or tag, noting that ZF1 has been modified
for line voltage other than what it was specified for. This may prevent accidental use on an
incorrect line voltage in the future.
L1
AC
INPUT
LINE
X1
LOAD
L2 X2
GROUND
CONTROL
Figure 3.4 Typical ZF1 Line and Load Connections

ZF1 SCR Power Controller Operation
Rev 3 Ametek HDR Power Systems 11
CHAPTER 4 - Operation
4.1 General
This Chapter provides information necessary for proper setup and operation of various methods used
to control the ZF1.
a. Front Panel indications
b. Command input control
c. Remote manual control with a potentiometer
d. Auto/manual control with a controller and potentiometer
e. On/off control
f. Shutdown
Figure 4.1 Control Panel
4.2 Front Panel Indicators
Control Power Indicator – A Red Light Emitting Diode (LED) located on the front cover of the unit
signals when the control power is present.
Command Signal Indicator - The Command Signal Indicator is a green Light Emitting Diode (LED)
located on the front cover of the unit. The brilliance of this LED will change with a current Command
Signal. The brilliance increases with an increased Command Signal and decreases with a decreased
Command Signal. The LED will not function with a voltage or manual input.
Blown Fuse Indicator - The Blown Fuse Indicator is a yellow Light Emitting Diodes (LED) located on
the front cover of the unit. Switch on the fuse controls the LED.
4.3 Command Input Control
The ZF1 is calibrated at the Factory for the specified input type and normally does NOT need
adjustment. However, should a setup be required use the following methods. Refer to chapter 3.5 for
the Command signal input configuration.

Operation ZF1 SCR Power Controller
12 Ametek HDR Power Systems Rev 3
a. Set the ZERO and SPAN controls fully CCW (counterclockwise).
b. Connect a voltmeter across terminals X1 and X2 of the ZF1. Set the voltmeter range to measure
full input voltage.
c. Close the fused disconnect or circuit breaker to apply power to the ZF1. Turn the Process
controller on and set to demand zero power output.
Figure 4.2 Process Controller Input Connections
d. Adjust the ZERO control CW until the output just turns on, then turn the ZERO control CCW just to
the point where the output voltage reading is zero.
e. Set the Process controller to demand 100% output. Observing the voltmeter, adjust SPAN CW
just to the point where the reading is below the maximum output voltage. Then adjust SPAN CW
just to the point where the meter reading is at maximum.
Note: The output voltage measurement on Zero Fired Power Controllers with a digital voltmeter
will be erratic except at full output. This is due to the variable pulses to regulate the output.
f. Repeat steps 4.3f and 4.3e as necessary, to ensure proper control adjustments have been made.
g. Turn off the line power to the ZF1 and disconnect the test equipment. The ZF1 is now ready for
automatic operation.
4.4 Remote Manual Control with a Potentiometer
Some applications only require a manual control input and not a closed loop input from a process
controller. This potentiometer may be located on a remote panel near other controls related to the
process being powered by the ZF1. It may be calibrated to correspond to a percentage of rated power
output, process temperature, or some other parameter. The potentiometer may by 500 Ω to 5 kΩ, and
should be rated at 1/2 watt, minimum.
a. With the power to the ZF1 turned off, connect the potentiometer as shown in Figure 4.3. The CW
position is the full power output position. Terminal TB1-5 is internally connected to a positive dc
voltage source.
b. Connect a voltmeter across terminals X1 and X2 of the ZF1. Set the voltmeter range to measure
the full output voltage.
c. Set the SPAN control and remote potentiometer fully CCW.
d. Close the fused disconnect or circuit breaker to apply power to the ZF1. The unit should be
energized, with no output.
WARNING - ELECTRIC SHOCK CAN KILL
HAZARDOUS VOLTAGES exist at the output terminals and at the load when
the input voltage is connected. This condition exists even when the Controller is
set to deliver zero output. Always remove power and properly lock out power to
the unit before attempting any service, including the load.

ZF1 SCR Power Controller Operation
Rev 3 Ametek HDR Power Systems 13
Figure 4.3 Remote Control with a Potentiometer
e. Adjust the ZERO control CW until the output just turns on, then turn the ZERO control CCW just to
the point where the output voltage reading is zero.
f. Set the SPAN control and remote potentiometer fully CW. The output should be full-on.
g. Observe the voltmeter and slowly adjust the SPAN control CCW, just to the point where the output
voltage reading is at maximum.
h. If necessary, readjust ZERO with remote potentiometer fully CCW and SPAN control and remote
potentiometer fully CW.
i. Turn off the line power to the ZF1 and disconnect the test equipment.
4.5 Auto/Manual Control with a Controller and Remote Potentiometer
On closed loop processes it may be desirable to be able to operate the unit manually. The SCR Power
Controller has this capability designed into it. Connect the Command Signal, a Remote Manual control
and an Auto/Manual switch in the Auto position. By switching to the Manual position, the Remote
Manual control operates and the auto signal is disconnected.
With the power to the PF1 turned off, connect the switch, potentiometer, and controller as shown in
Figure 4.4 and remove jumper from terminal TB1-7 and TB1-8. Install the AUTO/MAN switch in the
same general location as the remote manual potentiometer. Note that the full CW position of the
potentiometer is the full-power-output position.
Figure 4.4 Auto/Man Control with Controller and Remote Potentiometer

Operation ZF1 SCR Power Controller
14 Ametek HDR Power Systems Rev 3
Place the AUTO/MAN switch to AUTO and calibrate the system as described in steps 4.3b through
4.3h.
4.6 On/Off Control
Some applications require that a simple ON/OFF type control be used. The unit can be used in these
simple applications. It can be connected for turn on by a contact closure.
With the ZF1 configured for non-isolated inputs and the power to the ZF1 turned off, connect the
system as shown in figure 4.5. A closed contact will turn on (enable) the ZF1.
Figure 4.5 On/Off Control
Calibrate the system by performing the steps in 4.3. Note that zero power demand is accomplished by
opening the contacts with the controller, and maximum power demand is present when the contacts
are closed.
4.7 Shutdown
When it is necessary to shutdown or disable the output, it is a simple matter. Connect a dry contact
closure between terminals 3 and 4 of the firing circuit as shown in Figure 4.6. A closed contact will
disable the ZF1 output.
Figure 4.6 Shutdown Control
(Output Disabled By Contact Closure)
WARNING
This method of control is not to be used with isolated inputs!