Delay Timers

you can either use on delay for process control or motor control. for example in a bidirectional motor a on delay is given by connecting 2 timer with contactors, as the contactor contcts delay will be given through the timer(both in hand or auto) similarly off delay is used to stop the motor in one direction and to contact in other direction. but precised delay will matter to get rid of surges or over torque etc.

on off delay timers r used where u want to switch on or switch off a current path after a particular period of time............these r u used in motor controls, synchronisations and in other expensive (hi-fi) panels............for example in a star delta starter, for the contacts to switch from star to delta we use a on delay timer........u can check telemecanique catalogue for timers ....

First of all, you need to know the purpose of using the timer. The purpose of using timer is to initiate a second action after a certain time of occurring the first action. When the first action occurs, there happen two cases:

(1) the timer is energized and its contacts operate, after the timer setting time, to initiate the second action

(2) the timer is de-energized and its contacts operate, after the timer setting time, to initiate the second action

The first case is called ON Delay timer and the second case is OFF Delay timer. Once you understand it, the use of ON Delay and OFF Delay depends on the circuit condition whether the timer requires energized or de-energized after the first action occurs.

- MS

Thats i need.

thanks a lot SHAMITHGAMBHIR1 & Ssamad.

One small amplification. There are "Power-off" delay timers and "Signal-off delay" timers within the definition of the Off-delay timer. The first type is usually pneumatic or chronometric, and does not depend on power being on. The second type is electronic and depends on control voltage being available. There are some applications where the power-off delay timer is required.... one is in refrigeration/airconditioning.

off-delay timer A type of timer in which the contacts change position immediately when the coil is energized, but delay returning to their normal position when the coil is de-energized.

on-delay timer A type of timer in which the contacts delay changing position when the coil is energized, but change back to their normal position immediately when the coil is de-energized.

One can get universal timers (not an endorsement) these days that allow programming of their output; one size fits all.