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Applications Guide

Delay-on-make TDR, Normally Open
( C, C10, DC10, ST1, ST1A, ST1D, SWDC, SWPDC, SWRDC Series)

Blower Motors
A normally open delay-on-make timer can be used to operate a blower motor which is to be delayed for a specified amount of time after an electric, gas, or oil heater has been started. This avoids movement of cold air into a room that is occupied by people.

A normally open delay-on-make timer can be used to operate a blower motor

Motors & Compressors
A normally open delay-on-make timer will provide staggered starting times for two or more motors or compressors which have been simultaneously activated by a main disconnect switch. This will avoid excessive power line surge current which would otherwise occur if all motors were to be started at the same time.

Burglar or Intrusion Alarms
It is normally desirable to delay the activation of an alarm when an authorized person enters a protected area. The time delay provides sufficient time for proper deactivation of the alarm.

Open Door Warning
The Delay-on-make timer relay can be used to provide a warning if a door (such as on a walk-in refrigerator) is left open for a sustained time. For normal door opening and closing, the timer does not complete its cycle, and is continually reset to zero each time the door is closed. Should the door be left open the relay will time out, causing the alarm to operate.

Power Supply Sequencing
Some electrical and electronic equipment utilize more than one power supply. It may be desirable to energize these supplies at separate intervals. The delay-on-make relay can control the start time of one or more power supplies after the main power switch is turned on.

Oven Ignitor Control
A normally open relay can be used to provide fail-safe operation of the electrical ignitor of a natural or propane gas fired oven. The current operated heater of the time delay relay and ignitor are connected in series, and after sufficient time has elapsed to bring the ignitor up to temperature, the relay contacts close. This powers the gas valve solenoid and allows the gas valve to open. Should the ignitor fail the gas valve remains closed.

Fan Control
The delay-on-make timer can be used to control the start time of a cooling fan so that it does not operate on short cycles, when doing so would result in excessive cooling.

Two Speed Motor Control
It is possible to achieve a “soft start” on a two speed motor by using a single pole double throw delay-on-make relay. The normally closed contact of the relays is connected to the low speed motor terminal, and the high speed terminal is connected to the normally open contact. When power is first applied, the motor starts in low speed, then switches to high speed when the time delay cycle is completed.


Normally Closed, Delay-On-Break TDR (C, C10, DC10, SWDC, SWPDC, SWRDC Series)

Normally Closed, Delay-On-Break TDR

Air Conditioning System
A normally closed delay-on-break TDR can be used to hold the blower motor in operation for a specified time after the cooling compressor has been turned off by the thermostat.  This allows the residual cooling effect in the evaporator coil to be used to provide additional BTU’s of cooling after the compressor has stopped.

Gas Valve Control System
Any electrically operated natural or propane gas ignition system must be monitored to ensure that ignition has occurred and a flame is present. The normally closed relay can be used to interrupt power to the gas valve solenoid in the event of a malfunction of the system.

Telephone Circuit Control
If there is no response to a phone call within a specified time, the delay-on-break relay can be used to terminate the call.

Dead Man’s Seat
Some mobile equipment must be automatically shut down when the driver leaves his or her seat. However, it is desirable that no shutdown occur if the seat switch experiences a short transient as would happen if the driver “bounced”. The normally closed time delay relay can provide the desired delay time before the motor is shut down.

Triggered Delay-On-Release TDR (CR, CR10, DCR10, STB Series)

Electric and Gas Dryers
The delay-on-release timer may be used to operate a motor or other electrical device, such as an electric or gas dryer, for a specified time.  In a commercial laundromat, for example, it is desired to operate the dryer for 10 minutes after a coin is inserted.  When the customer presses the start button, the dryer will run for the allotted time.

Triggered Delay-On-Release TDR

Amusement Rides
Amusement rides are generally time events, lasting for just a few minutes at a time. When the operator activates the start button, the driving motor is automatically started and shut down after the desired time interval.

Copy Machine Cooling Blower
Copy machines generally require a period of cooling after the last copy has been made. The triggered delay-on-release relay will provide the desired cooldown period.

Elevator Door Control
It is necessary that an elevator door’s closing be delayed for a specified time after the last passenger has entered or exited the elevator. The triggered delay-on-release timer can be used, in conjunction with a photoelectric sensor, to delay the closing of the door.

Garage Door Opener Light Control
Operation of a garage door opener typically illuminates the interior of a garage. The triggered delay-on-release relay can be used to provide automatic lamp shutoff after the desired time period has elapsed.

Photographic Exposure
Still photographs are taken with a specified exposure time. The triggered one-shot relay can be used to operate a photoflood lamp for any desired interval, milliseconds or more.

Pump Stations
The triggered delay-on-release relay may be used to operate a pump (such as an irrigation system) for a specified amount of time after a trigger signal is generated by a sensor.

Delay-On-Dropout TDR (DOD, HDOD Series)

Monitoring Line Power
It may be desired to monitor a power line for a sustained power loss. The DOD and HDOD relays will monitor line voltage, and after a specified time the relay contacts will transfer. For periods of dropout time less than the specified delay, the relay contacts will not transfer.

Blower or Pump Control
Many times it is desired that a blower, pump, or other electrical device remain in operation after shutdown of a piece of equipment. The DOD and HDOD relays will allow operation of these devices for a specified time after the main power source has been shut down.

Automotive Headlamp Control
It may be desired to operate the headlamps of a vehicle for a specified time after the driver has exited the vehicle. The DOD and HDOD relays will provide headlamp operation for the specified time, then automatically shut off.

Recycling timer / Flasher (D, DF, DF10, DFS, DFV, DFWS, SEQ Series)

Warning Light System
The flasher relay may be used to illuminate a single or group of lamps to provide a visual warning system. The flash rate may be selected for the best attention getting rate, depending upon the application.

 Silent Alarm
The DF flasher is a solid state two wire or two terminal device that is easily wired into a vehicular electrical system for the purposes of flashing a warning light, without the accompanying sound of an electromechanical device, in the event of an emergency such as a carjack or robbery.

 Electric Sign
Any of the recycling flashers may be used to control an electric sign when it is desired to produce a contact on/off sequence for increased awareness. The DFW and DFWS series are capable of controlling two sections of the sign, providing and alternating effect.

 Emergency Vehicle Warning Lamps
The DFW and DFWS wig-wag flashers are designed to alternately flash two sets of warning lamps, such as used on police, ambulance and other emergency vehicles. Other Amperite flashers may be used to control a single set of lamps.

 Brake Light and Headlamp Pulsators for Motorcycles and Other Vehicles
The Amperite STOP-ALERT Pulsator provides a rapid, continuous pulsating or glimmering effect on vehicle stop lamps. The STOP-ALERT 2 and STOP-ALERT 2M provide a series of ½ second pulses, then continuous illumination when the brakes of the vehicle are applied for more than 5 seconds. The HEAD-ALERT is used to enhance motorcycle headlamp illumination during daylight hours by adding a rapid glimmering effect. The HEAD-ALERT 2 modulator enhances motorcycle headlamp illumination during daylight hours and disables at night by way of a photo-electric sensor.

 Sequential Timer
The SEQ series is used to sequentially power individual loads, such as incandescent lamps. Units are available for two to four load circuits. Load current rating is 5 amperes. Typical applications include airport runway illumination, theater marquees and car wash signs.

Programmable Recycling Timer / Flasher (DFA/HDFA Series)

Electrical Equipment Burn-In
The DFA and HDFA series relays may be programmed for a desired “OFF” time and “ON” time. This can be used to run a piece of equipment for a specified time, and then shut off for a different specified time. The relay will cycle the equipment in this manner to provide on and off cycling for electrical burn-in tests.

Water or Sprinkler Control
A water valve or pump may be operated for a specified time and then automatically shut off. The cycle will then repeat in accordance with the programmed on time and off time.

Traffic Control
The DFA and HDFA recycling relays can be programmed for two different intervals (Off and On) that control a traffic light system, using the two DPDT relay contacts.

One-Shot or Interval Timer (CI, CIR, ST2)

Burglar Alarm
When an intrusion is detected, it may be desirable to operate an alarm bell or siren for a specified time. The one-shot relay will provide a timed interval to operate the alarm or other device.

Automatic Outside Mirror or Rear Window Defroster
It is desirable to have an electrical heater automatically shut down after the unit has been activated. This will avoid the possibility of vehicle battery depletion.

Heat Sealing Machinery
A specified time of operation is required for the heating element to be energized. The one-shot relay will provide an automatic timed interval.

Spot Welding Machine
Electric welding machines require a timed cycle, usually adjustable, for proper spot welding. The one-shot relay will provide an adjustable weld time.

Automotive Seat Belt Warning
When the driver starts the vehicle, it is desired to operate a seat belt warning (buzzer and/or light) for a specified time when the seat belt was not used. The interval or one-shot relay can be used to provide the desired operate time of the warning annunciator.

Truck or Trailer Interior Light
Trucks and trailers often have manually operated lights which illuminate the cargo area. Many times the user will turn on the light but forget to turn it off, resulting in a dead battery. The ST2 series interval relay is an ideal solution that permits the light to operate for a specified time, then automatically turns it off.

Dispensing Equipment
Dispensing equipment typically needs a specified time to deliver the correct quantity of a product. The one-shot or interval timer is ideal for this purpose.

Timed Interlock
The triggered interval delay relay can be used to release a lock for a specified length of time, then automatically relock the system. This prevents the interlock from being left in an opened position.

Pump Stations
The timed interval relay is useful to operate a pump for a specified amount of time, as in an irrigation system where a lawn, garden or farm requires watering.

Vehicle Starter Interlock
The starter motor of a vehicle may be protected against continuous operation that may cause overheating by using the Amperite interval relay to automatically disconnect power after a specified interval.