Contactor with timer, how to assemble?


Do you know what a timer relay is and how to connect a timer relay? In this article the World of Electrical shows how to time the activation of a contactor is to connect contactor and timer relay with diagram.

There are many machines, industrial processes and even lighting systems that need timing, that is, something that needs to be turned on or activated at a specific time.

Timer Relay

The timer relay, or also known as the time and timer relay , is the term used to refer to any relay that performs switching operations according to the time that is set, after this time your contacts switch. Its application is frequent in industrial processes, such as in motor starters, industrial ovens, electrical control panels, etc.

The model of timer relay that we are going to use in the assembly of the control, makes it possible to regulate the activation time of the relay in seconds, minutes or hours. Another great advantage is that this time relay model can be used as a power-up delay or power-up pulse.

Timer relay in seconds, minutes and hours.

In this assembly we will use a circuit breaker , a timer relay, a contactor and a two-position selector switch . The purpose of the command is for the timer to activate a contactor after a certain time after the circuit has been activated .

Components used to connect the time relay with contactor.

Before starting the assembly, it is necessary to understand the contacts of the timer relay. See in the image below, that time relay has two contacts for its supply, A1 and A2, terminal A1 is at the top and terminal A2 at the bottom of the timer relay. The time relay also has a reversible contact, that is, a common contact which is 15, a normally closed contact represented by 16 and a normally open contact represented by 18.

Timer relay contacts to make the connection.

Control assembly

The assembly is very simple, generally professionals have more difficulty in setting the timer. Our supply system is two-phase 220V, so we will use a bipolar circuit breaker to protect the circuit.

From the output of the first pole of the circuit breaker, we will connect cable 1 to the normally open contact of the selector switch.
From the open contact output of the selector switch, we will connect cable 2 to contact A1 of the timer relay, and we will derive a cable for the common contact 15 of the timer rela

Connection of cables 1 and 2, already prepared.

From the normally open contact 18 of the timer relay, we will connect cable 3 to contact A1 of the contactor. From the second pole of the circuit breaker, we will connect cable 4 to the A2 of the timed relay, and branch to the A2 of the contactor.

Connection of cables 3 and 4, already prepared to finish the command.

Thus, finalizing the assembly of the command, now it is only necessary to adjust the time and activate the timer relay.

Timer relay regulation

At the front of the timer relay we have 3 selector discs. The first selector disk has a scale ranging from 10% to 100%, this scale is responsible for regulating the time according to the scale selected in the second selector disk.

In the second selector disk there are 7 scales, 1 second, 10 seconds, 1 minute, 10 minutes, 1 hour, 10 hours and 100 hours. So if for example I want to set the timer for 3 seconds and only select the first selector dial at 30% and the second at the 10-second scale. The third selector disk is the one that defines if it is delayed on energization or pulse on energization.

At the front of the timer relay we have 3 selector discs.

What is energization delay or energization pulse?

When selecting the power-on delay, the timer relay starts counting the time as soon as it is powered. Then, when the selected time passes, the relay arms and closes the NO contact. See the image below for an example of a delay in energization, our time is selected in 3 seconds and when turning the selector switch, only after 3 seconds that our contactor is activated.

Delay in energizing the time relay.

And when you select the pulse on power up, the timer relay arms the relay and starts counting the time at the same time. Then, when the selected time passes, the relay will trip. Observe in the image below an example of a pulse on energization, our selected time is 3 seconds, as soon as the selector switch is turned, the contactor will activate instantly and after 3 seconds the contactor will be turned off.