Product Catalog

M.C. Miller JR1

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Rechargeable M.C. Miller JR1 35 amp AC/DC interrupter.


  • 35 amp AC/DC interrupter
  • Crystal controlled timing
  • Rechargeable battery
  • Immediate or delayed interrupting operation
  • Low battery indicator
  • Countdown and relay status indicators
  • On and off cycle times up to 999.9 seconds
  • Synchronized operation with any number of JR-1s and JR-2s

General Information:

MCM's Model JR-1 is a computer age successor to the Model CI-30. The use of a microprocessor and crystal controlled timing result in a unit which can operate alone or in precise synchronization with any number of other JR-1s or the 100 amp Model JR-2.

This feature facilitates measurement of instant-off polarized potentials. The JR-1 is also well suited for use where more traditional current interrupter applications are required.




Custom LCD, wide operating temperature range, -20°C to +85°C (-4°F to +185°F) with enhanced response time at extremely low temperatures. Large(.7" high) digits plus equipment status annunciators.


CMOS Microprocessor, 8-bit; EPROM operating system. EEPROM, initializes prior setting on power up.


Sealed, Tactile feedback; 4x4 Matrix; "0-9"; "←"; "ENTER"; "CLOCK SET"; "START SET"; "ON CYCLE"; "OFF CYCLE" Keys.

Cycle Range:

Keyboard Programmable: .1 to 999.9 seconds in .1 second increments either "ON" or "OFF" cycle.

Auto Turn-on:

Preset interrupt start time eg. 0700

Night Latch:

The JR-1 supports 24-hour timing and a scheduled relay closure period. For example, a night latch time of 1700 could be entered from the keypad, and a start time of 0700. The unit will operate normally until 1700, at which time the relay will close and will stay latched until 0700 the next morning, then the normal interrupt cycle will begin again. This feature facilitates full CP polarization during hours when the survey crews are absent.


Timing: 0.5 second maximum variation in 24 hours. Synchronization to within 1 millisecond.

Relay Start Position:

Selected by toggle switch.


Latching type; 35A @ 28 volts DC or 125 volts AC.


Sealed, rechargeable, 6 Volt, 2.6A/H Charger supplied.

Battery Life:

Greater than 50 hours continuous (worst case) .


10" H x 10.75” W x 5” D


approx. 7lbs.(3.18 Kg)