The MC3-MI controls National Time's MI Series of Impulse Architectural Clocks which include the 3MI, HMI, 4MI etc. The MI Series minute impulse clock movements increment each minute during normal timekeeping and will move 1 minute every 10 seconds during corrections. The MC3-MI comes standard with three solid-state 120VAC outputs to directly control clocks without the need for additional relays. These solid-state outputs are capable of driving 3 amps each and incorporate zero-cross technology to handle undesirable current surges and inrush.

The MC3 uses power-line frequency to keep accurate time eliminating the inaccuracies of crystal oscillators found in other products. In countries that do not regulate the power-line frequency or installations that frequently test backup power generators, the power-line frequency will not be an acceptable time base. For these installations, a minute impulse clock system should be used. The MC3 can be equipped with a Global Position Satellite (GPS) antenna (ordered separately) to keep time with the National Institute of Standards and Technology (NIST) satellite time base. The MC3 series master clocks also automatically correct clocks after a power outage or daylight savings adjustment. The MC3’s battery-less backup design can keep time internally for over 150 days.

The MC3-MI can control one Architectural Clock in its standard configuration. For multiple clock installations, the MC3-4SW (ordered separately) 4-switch module is required. The 4-switch module provides individual clock control so the clocks can be synchronized with each other to allow the MC3 to advance them to the correct time together.

Accessories

MC3-4SW 4-Switch Module. The MC3-4SW allows one MC3 to control up to four Architectural Clocks and is required for multiple clock installations. The 4-Switch Module has four individual clock control switches to synchronize the clocks to allow the MC3 to correct them together. 

MC3-GPS Antenna. The MC3-GPS module enables the MC3 to receive accurate time information from up to 12 satellites. The communication between the MC3 and GPS antenna is supervised. During fault conditions, the master clock uses power-line frequency to keep time accurate. The standard outdoor mounting requires a 1” x 14 TPI pole (by others). The GPS antenna comes standard with a 30’ cable. Cable length may be extended to 100’ with 5 conductor shielded low capacitance cable.