• Banner
ATS MX Contactor

Caterpillar and your local Cat® Dealer are ready for all your power generation demands. From diesel and gas generator sets to uninterruptible power supplies, automatic transfer switches and electrical switchgear, our experienced worldwide dealer network can deliver the power systems and support you need.

CTG Series Automatic Transfer Switch


The Cat® CTG Series Automatic Transfer Switches (ATS) are pre-configured for applications requiring the dependability and ease of operation found in a full feature power contactor type transfer switch.

CTG switches are equipped with the next generation MX150 microprocessor panel, which controls the operation and displays the status of the transfer switch’s position, timers and available sources. As an embedded digital controller, the MX150 offers high reliability and ease of unattended operation across a range of applications.

Product Details

Technical Summary

Rating Range 40-3000A
Transfer Type Open transition
Switch Type Contactor based
  • Standard Features
    •  Auxiliary Contact: <br>Closed when the switch is in the emergency position <br>(Additional contacts optional)
    •  Auxiliary Contact: <br>Closed when the switch is in the normal position<br>(Additional contacts optional)
    •  7, 14, 28 day interval timed exerciser, pushbutton/timer operation
    •  Engine Start Contact
    •  Indicating LED Pilot Lights: <br>-Switch in emergency position <br>-Switch in normal position <br>- Normal source available <br>-Emergency source available
    •  Time Delay to Engine Start: Standard setting 3 seconds, adjustable 0-10 seconds
    •  In-Phase Monitor, self-adjusting (Not available on CTGD models)
    •  Time Delay on Retransfer to Normal: To delay retransfer to normal source (immediate retransfer on generator set failure); standard setting 30 minutes, adjustable 0-60 minutes
    •  Push button Bypass of time delay and normal emergency
    •  Test Switch - Momentary
    •  Event Log OD 16 Event that track date, time, reason and action taken
    •  Voltage and Frequency Indication for S1 and S2
    •  Peak Shave/Remote Load Test: Input for peak shave or remote load test; includes automatic return to normal if emergency source fails and normal is present; 120 VAC
    •  When specified for use with a CTGD Series delayed transition switch, the control panel also includes the following:
  • MX150 Control Panel
    •  Time Delay for Engine Cool Down: Allows engine to run unloaded after switch retransfer to normal; standard setting 5 minutes, adjustable 0-60 minutes
    •  Time Delay on Transfer to Emergency: To delay transfer to emergency after verifying emergency source available; standard setting 1 second, adjustable 0-5 minutes
    •  Timer and voltage/frequency settings adjustable without disconnection from power sources
    •  Built-in diagnostics with LCD display for immediate troubleshooting
    •  LED/LCD indicators for ease of viewing and long life
    •  Nonvolatile memory (exerciser battery backup not required for standard operation)
    •  Processor and digital circuitry isolated from line voltage
    •  Inputs opto-isolated for high electrical immunity to transients and noise
    •  Communications header for network interface
  • Options
    •  Plant Exerciser, clock type (load/no load): Allows the generator to start and run unloaded or to simulate a power failure, start generator and run under load (7-14-28-365 days, user selectable)
    •  Space heater and thermostat
    •  Network communications interface card (LonWorks / ModBus)
    •  Maintained Test Switch
    •  Maintained Test Switch w/Keypad
    •  Service entrance configuration
    •  Auxiliary Contact, operates on Source 1 line failure
    •  Auxiliary Contact, operates on Source 2 availability
    •  Auxiliary Contacts: Closed when the transfer switch is in Source 2 position
    •  Auxiliary Contacts: Closed when the transfer switch is in Source 1 position
    •  Disconnect Switch: Permits transfer in “AUTO” position and inhibits transfer in “INHIBIT” position. (Standard 800A and above)
    •  Elevator Pre-Signal Auxiliary Contacts: Open 0-60 seconds prior to transfer to either direction, re-closes after transfer
    •  Universal Motor Load Disconnect Circuit: Auxiliary Contact opens 0-60 seconds prior to transfer in either direction, re-closes after transfer. Can be configured by end user for Pre-transfer, Post-transfer, or both.
    •  Voltage Imbalance Monitor (Three Phase)
    •  Lockable, see-through cover for ATS controller
    •  Power Measurement Meters
    •  Note:For applications requiring additional options or other configurations, see the CTS Series fully configurable transfer switch.
  • Plant Exerciser, clock type (load/no load): Allows the generator to start and run unloaded or to simulate a power failure, start generator and run under load (7-14-28-365 days, user selectable)
    • Space heater and thermostat
      • Network communications interface card (LonWorks / ModBus)
        • Maintained Test Switch
          • Maintained Test Switch w/Keypad
            • Service entrance configuration
              • Auxiliary Contact, operates on Source 1 line failure
                • Auxiliary Contact, operates on Source 2 availability
                  • Auxiliary Contacts: Closed when the transfer switch is in Source 2 position
                    • Auxiliary Contacts: Closed when the transfer switch is in Source 1 position
                      • Disconnect Switch: Permits transfer in dquo;AUTO” position and inhibits transfer in dquo;INHIBIT” position. (Standard 800A and above)
                        • Elevator Pre-Signal Auxiliary Contacts: Open 0-60 seconds prior to transfer to either direction, re-closes after transfer
                          • Universal Motor Load Disconnect Circuit: Auxiliary Contact opens 0-60 seconds prior to transfer in either direction, re-closes after transfer. Can be configured by end user for Pre-transfer, Post-transfer, or both.
                            • Voltage Imbalance Monitor (Three Phase)
                              • Lockable, see-through cover for ATS controller
                                • Power Measurement Meters
                                  • Note:For applications requiring additional options or other configurations, see the CTS Series fully configurable transfer switch.
                                    Built for it