Electronic Timer With Power Isolation TDI

The TDI-20 is a heavy-duty, trapped key interlock switch controlled by a fail-safe timer and solenoid. The unit is designed to control access to hazardous machines with rundown times and can be used in high-risk, category 4 applications.

The unit incorporates a dual channel fail-safe timer; heavy-duty, continuously rated solenoid; solenoid position monitoring; 20A isolation switch; front panel lamp indication of signal and timer failure; up to three lock centres for multiple-access applications and an isolation switch lock-out feature.

Depending on the number of access points requiring control, this box would work in conjunction with Access interlocks.

TDI Electronic Timer With Power Isolation Data Sheet  |   TDI Electronic Timer With Power Isolation

When the machine running down, the access keys are trapped and the switch contacts 3N/O 3N/C. Turning the isolation switch to the off position changes the contacts to the switch and initiates the timer. After a pre-set time (set to the run down time of the machine) the timer energises the solenoid and releases the access keys. The keys can now be transferred to the access interlocks fitted to the perimeter guard of the machine. In this condition, the isolation switch cannot be returned to the 'on' position. The isolation switch can also be 'locked off' with a padlock as an additional safety measure. The position of the solenoid is monitored by two safety switches. This feature enables an external dual channel safety relay to be connected to the two normally closed contacts of the safety switches. The safety relay will prevent the machine from being re-started in the event of solenoid failure.