Learn Some Basics about Time Delay Relays

Posted by Meba Electric on July 14th, 2021

No matter what the application is but when you require a definite-purpose solution then timer relay can provide reliable, simple, and economical control. Adjusting the delay time is very much simple as turning a knob. TDRs are very much used in industrial applications and OEM equipment. Along with this, for targeted logic needs, such as in a small panel or in sub-panels they play an important role. They have a large variety of features and operating characteristics, such as economy, simplicity, compactness, and ease of use.

In the case of a standard control relay, when voltage is applied to the coil contacts close immediately, and when voltage is removed it opens immediately. In different types of applications, it is necessary to have a delay in the operation of the contacts which is then followed by application or removal of voltage. A TDR solves the problem quite easily. After the application of voltage, there are some TDRs who postpone the closing of the contacts while there are others who close the contacts and after a delay then reopen them.

5v timer relay is also available as a plug-in device. You will also find them in a range of other forms, including base-mounted devices and direct IEC DIN-mounted controls. A TDR can even be fixed on a motor starter. In this application, the timing function begins by energizing the motor starter, and when the timing has completed the contacts within the device start operating. Instead of relay outputs, there are some TDRs that have solid-state outputs.

In traditional times, TDRs were available only as single-function, single-time-range devices. Still, these devices are available and in applications where the timing needs to be locked in, they are typically used. Today, with multiple timing ranges and functions many TDRs are available. These TDRs costs little more than single-function devices and have wide control voltage ranges. In addition, for reduced inventories newer multifunction IEC-style timers are allowed. Let’s take a look at the more common types of TDRs.

On-delay timers

In an on-delay timer, timing begins when voltage is applied. The contacts close when the time has expired and it still remains closed until the voltage is removed from the coil. The time delay resets If voltage is removed before time-out.

Off-delay timers

When there is the use of an off-delay timer, nothing happens during the application of voltage. Contacts are transferred by the closure of control input (SW). Prior to time-out closing the control input causes the timing to reset and prior to time-out removing voltage resets the timing and also opens the contacts. Generally, after the input voltage is lost true off-delay timers provide this functionality (keeping contacts closed). Even if the timer loses power they have capacitors to keep contacts closed.

For the on-delay and off-delay timers, there are special contact symbols. However, these are the only 24v timer relay for which special contact symbols have been assigned. The same contact symbols that were used for relays are used by other types of TDRs. Often; to denote the operating condition a note is made near the relay symbol. With the removal of voltage, the state of relay contacts is always shown.