Wiring Control (Trigger) Switches from Multiple Time Delay Relays in Parallel
Tuesday: February 21, 2017 : Time Delay Relays
I have the control switches from 5 separate OFF Delay time delay relays from other manufacturers wired in parallel so one switch can operate all 5 at once. However, when I replaced one of the original units with yours, the Macromatic product operated once and then stopped working. What’s wrong?
I have the control switches from 5 separate Macromatic TR-616 Series OFF Delay time delay relays manufactured prior to 2017 (date code 5216 or earlier) wired in parallel so one switch can operate all 5 at once. However, when I replaced one of the original Macromatic timers with a new TR-6 Series product introduced in early 2017, some of the old Macromatic products operated once and then stopped working. What’s wrong?
All time delay relay functions that are initiated with a control switch (typically Off Delay, Single Shot, Watchdog & Triggered Delayed Interval) have some level of voltage across the control switch pins (usually 5-6). In the case of most Macromatic products, that voltage level is 10V DC. However, the new TR-6 Series products introduced in early 2017 and most other competitors’ products incorporate what is called a line voltage trigger.
A line voltage trigger is where the voltage across the control switch terminals is equal to the input voltage supplying the time delay relay. A time delay relay with an input voltage of 120V would have 120V across the control switch terminals. One with 24V input voltage would have a 24V trigger. Normally, it makes no difference whether you use a time delay relay with a line voltage trigger or one with a 10V DC trigger. However, there are two important scenarios of concern:
• Any time you have mixed brands of time delay relays triggered from the same control switch, you must do a careful review of the application when replacing any unit to ensure the trigger voltages of each unit are the same. If any of the units have a trigger voltage lower than the others, they could be damaged and become inoperable when the control switch is connected.
• You have several older Macromatic TR-6 time delay relays all triggered off the same control switch and now you are replacing one of them with a new TR-6. All the original TR-6 products would have a trigger voltage of 10V DC but the new one would have a line voltage trigger (i.e., 120V equal to the input voltage). The higher trigger voltage of the new TR-6 would likely damage the trigger circuitry of the existing TR-6 products and make the old units inoperable.
Unfortunately, the best solution to both issues is to replace ALL the older time delay relays with the same version so trigger voltages are the same. Macromatic does offer several options if you want to replace a competitor’s product whose trigger voltage is equal to the input voltage of the product. The Macromatic TR-5 Series & TD-8 Series products are available with an optional line voltage trigger. Add a “-T15” suffix for 11 pin products or a “-T14” suffix for 8 pin products to the catalog number and enter the complete catalog number in the search box above, i.e., TR-51622-05T15. This search will provide a drop-in replacement for the TR-5 & TD-8 Series products. The new TR-6 Series products introduced in early 2017 have a line voltage trigger.
Please contact Macromatic at 800-237-7474 for more information.
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