Timers and Time Delay Relays
CARLO GAVAZZI is a market leader in timers and time delay relays with one of the broadest range of products in the industry. With over 40 years of experience, Carlo Gavazzi knows what it takes to manufacture timers that are designed to withstand the rigors of your toughest applications. With local sales and support centers located in 22 countries and independent distribution in over 100 countries, CARLO GAVAZZI product and technical support is available around the world.
CARLO GAVAZZI's Timers are used in a broad range of applications. Typical applications include motor control centers, process timing, HVAC, and pump management. Our product range covers most timing functions including On Delay, Interval, Off Delay, Recycler, and Star-Delta types. We offer both single and multi-function timers and are available with either a DIN mount or plug-in housing.
Multi-Function Timers offer many timing functions in a single timer - which the user can select with either a rotary switch or DIP switch. Customers and distributors appreciate the value in having a single timer that can do many different functions.
Timers can be started either by applying the supply voltage to the timer (Automatic Start) or via a contact input (Manual Start).
On Delay Timers
When power is applied to the timer, the timer waits for a period of time before turning on the output. This is a very common timing function in motor and pump control circuits.
For manual start, the timing is initiated via a contact input. Timing can start on either the leading edge or trailing edge of the contact closure.
Interval timers are also known in some cases as 'One Shot' Timers. With an automatic start Interval Timer, when power is applied to the timer, the output turns on immediately and stays on for the the time period set by the user and then turns off.
For manual start, the output turns on when the contact is closed. After the set time period, the output turns off - even if the contact input is still closed.
Off Delay Timers
An Off Delay Timer with automatic start is also know as a 'True Off Delay' Timer. When power is applied to the timer, the output turns on immediately and stays on as long as power is applied. When power is removed, the output remains on for the time period set by the user and then turns off.
For manual start, the output turns on and stays on when the contact is closed. After the contact is opened, the output remains on for the time period set by the user and then turns off.
There are two types of Recycler Timers - Symmetrical and Asymmetrical.
When power is applied to a Symmetrical Recycler Timer, the output alternates between on and off as long as power is applied. There is a single adjustment for the timer setting and the ON Time and OFF time are the same. This type of timer is sometimes refered to as a 'Flasher Relay'.
An Asymmetrical Recycler Timer is similar to a Symmmetrical Timer - the difference being the ON time and OFF time are individually adjustable by the user.
With both types of Recycler Timers, it is selectable whether it starts with the ON time or OFF time first.
Star-Delta Timers, as their name suggests, are used to control Star-Delta Motor Starting. This is used on large motors to minimize the inrush current.
When power is applied to the timer, the first output (Star Timing) turns on to switch a contactor to start the motor in star connection (reduced voltage start).
The motor stays in the star connection for the time period set by the user. After this time elapses, output 1 turns off and after a short delay, output 2 turns on which switches a contactor to change the motor to a delta connection.
We have created an Online Training Course for our Timers consisting of 3 modules. These modules cover the technical aspects of timers and timing functions. In addition it also covers the applications and markets where these products are used.
Our Product Range
When motors are started, there is a large inrush current. If multiple motors were to all start at once, the resulting current surge can cause a significant voltage drop on the power lines. It is common to have an ON Delay Timer for each contactor to prevent all motors from starting at the same time.
For large motors where it is prohibitively expensive to use a soft starter or drive, a Star-Delta Timer can be used with contactors to start the motor for a period of time in the star position, and then to switch it over to delta to apply full voltage to the motor. This results in a reduction of the inrush current.
In a ventilation systems, the ducts should be open before the fan is started. An On Delay Timer that also has an instantaneous contact is commonly used. The timer gets the start signal which turns on the instantaneous contact which in turn operates the duct vents. After a period of time the delayed contacts turn on the ventilation fan.
Another popular application is to use an Off Delay Timer to switch on the fan in forced air gas and electric heaters. After the heater is shut-off, the timer will keep the fan running for a period of time to prevent damage to the heater element.
Water hammer is a common problem in pipes in pumping applications. It can also be a problem within the pump itself if a pump is started, stopped and then started again too quickly. If the pump is started too soon, the water column could still be travelling back down the discharge pipe or outlet causing the impeller to spin in the opposite direction. Starting the pump while this is happening can be damaging to the pump.
An On Delay Timer is used to prevent the pump from starting too soon.
With process equipment an Interval Timer is frequently used to allow the operator to set the duration of a process. The timer is frequently mounted through the front of the panel allowing the operator to adjust the time duration of the heater, pump, motor, etc. Typical applications include conveyor driven ovens and bakery systems.
The operator would press a button on the panel to start the process and even if the button is kept pressed, the process will only run for the set period of time. This prevents the process from continuously running.
Public swimming pools and hot tubs often require users to shower before they use the facilities. To prevent users from wasting water by leaving the water running after they are finished, an Interval Timer is used to control an electric valve.
With an Interval Timer, once the user presses a button the timer turns on for a set period of time and then shuts off.
Industrial equipment require periodic maintenance which also includes lubrication of linkages and gears. To ensure that the equipment actually receives the required lubrication, an Asymmetrical Reclycler Timer is used.
An Asymmetrical Recycler Timer has a separately adjustable on time and off time. For example, the On time could be set for 2 seconds and the Off timer for 24 hours. This example would operate an oil pump to provide lubricating oil each day. No more forgetting to lubricate the machinery.
In agriculture and aquaculture, it is important that feeding be done at regular intervals. In many cases there is no extensive automation backbone in place, so a simple timer is all that is required. In applications like this, an Asymmetrical Reclycler Timer is used.
An Asymmetrical Recycler Timer has a separately adjustable on time and off time. For example, the On time could be set for 30 seconds and the Off timer for 8 hours. In This example, a pump would be activated to supply feed to the holding tanks every 8 hours.