Common sense time delay relay circuit.

CASSETTE DECK

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#1
Common sense time delay relay circuit

I have a simple circuit for a time delay relay that really is child's play / Kinderspiel. It's just a voltage regulator error amplifier modified by adding a capacitor to the usual zener diode / resistor network on the base of a transistor and a relay coil with a commutating diode on the collector.

The 1N4001 discharge diode and is not essential for operation of the circuit but may be desirable in applications requiring a fast reset. The discharge resistor is not required if another circuit running off the same power supply draws sufficient current at low voltage. Suggested value for charge resistor 10K ohm at 12 volts. Suggested transistor BC337. Suggested value for discharge resistor 3.0K ohm. The time delay can be adjusted by changing the value of the charge resistor, capacitor or voltage of the zener diode. The zener diode can be a higher voltage, but can't be any lower than 5.1 volts because very low voltage zener diodes tend to have unpredictable characteristics a low current levels. For 5 volt operation of timer circuit use a LED in place of zener diode and change capacitor value to at least 1000uF for a similar time delay.

DSC00030.jpg

This circuit is useful in de thump for amplifiers and inrush limiters for switch mode and other types of power supplies. Some types of transformers, especially toroidal draw a very large surge of current from the AC mains until the core is magnetized. This circuit can be used in combination with a surge rated power resistor protected by a thermal cut out in these inrush limiting applications. The relay can be connected in parallel with a triac set up with another timer and trigger circuit with zero voltage crossing detection such as an opto triac driver with a zero voltage crossing detection circuit built in, to prolong the life of relay contacts.
 
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premiumplus

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#3
I have a simple circuit for a time delay relay that really is child's play / Kinderspiel. It's just a voltage regulator error amplifier modified by adding a capacitor to the usual zener diode / resistor network on the base of a transistor and a relay coil with a commutating diode on the collector.

The 1N4001 discharge diode and is not essential for operation of the circuit but may be desirable in applications requiring a fast reset. The discharge resistor is not required if another circuit running off the same power supply draws sufficient current at low voltage. Suggested value for charge resistor 10K ohm at 12 volts. Suggested transistor BC337. Suggested value for discharge resistor 3.0K ohm. The time delay can be adjusted by changing the value of the charge resistor, capacitor or voltage of the zener diode. The zener diode can be a higher voltage, but can't be any lower than 5.1 volts because very low voltage zener diodes tend to have unpredictable characteristics a low current levels. For 5 volt operation of timer circuit use a LED in place of zener diode and change capacitor value to at least 1000uF for a similar time delay.

View attachment 13783

This circuit is useful in de thump for amplifiers and inrush limiters for switch mode and other types of power supplies. Some types of transformers, especially toroidal draw a very large surge of current from the AC mains until the core is magnetized. This circuit can be used in combination with a surge rated power resistor protected by a thermal cut out in these inrush limiting applications. The relay can be connected in parallel with a triac set up with another timer and trigger circuit with zero voltage crossing detection such as an opto triac driver with a zero voltage crossing detection circuit built in, to prolong the life of relay contacts.
Nice! I've been looking for a time delay to add to my system's AC power control, I made up a high power switching relay to turn my entire system on and off. Only problem is that the inrush of everything (with TWO WOPL 1000 amps) causes my 20 amp branch circuit breaker to open up every several times I power up. So I need to delay one of the amplifier's power by a couple of seconds.
Looks like this would work well with a 12 volt supply for the circuit and relay coil.
 

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#5
Nice! I've been looking for a time delay to add to my system's AC power control, I made up a high power switching relay to turn my entire system on and off. Only problem is that the inrush of everything (with TWO WOPL 1000 amps) causes my 20 amp branch circuit breaker to open up every several times I power up. So I need to delay one of the amplifier's power by a couple of seconds.
Looks like this would work well with a 12 volt supply for the circuit and relay coil.
Joe has addressed that also....http://forums.phxaudiotape.com/showthread.php/4984-Stephen-s-Monster-Mono-s/page2 needed some for the monster mono's and he has some boards....
The method I would prefer to use for the Monster Mono or any load of a similar power level is a 3 stage turn on followed by a 2 stage turn off, instead of a 5 stage turn on.
-----------------------------------------------------------------------------------------------
Turn on stage 1: Low current (10A) solid state relay (SSR) in series with surge rated power resistor with thermal switch cutout turns on. The resistor limits surge current to a safe level. Thermal cutout trips in the event of failure of stage 2 circuit.

Turn on stage 2: High current solid state relay (SSR) with zero voltage crossing detector circuit turns on after 3 second time delay to bypass low current solid state relay (SSR) in series with power resistor. This is to prolong the life of the electro mechanical relay (EMR). The high current solid state relay (SSR) has a maximum continuous rating of 25A RMS, 250A surge. Maximum voltage drop at full load 1.5V RMS.

Turn on stage 3: High current electro mechanical relay (EMR) turns after 1 second time delay on to bypass solid state relay to reduce voltage drop and losses to maximize power available for power amplifier and other power circuits.
-----------------------------------------------------------------------------------------------
Turn off stage 1: Electro mechanical relay (EMR) contacts open.

Turn off stage 2: Both solid state relays turn off after a 1 second time delay. This is to prolong the life of the electro-mechanical relay (EMR) contacts.
 
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CASSETTE DECK

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#7
There are no contacts in any of the solid state relays (SSR).
This 3 stage turn on method uses two solid state relays (SSR)(or triac + driver equivalent) + one electro mechanical relay (EMR) to bypass the solid state relays to reduce voltage drop. A typical 1.2 volt drop across the solid state relay (SSR) is 1% of the 120V AC mains voltage. Quite a substantial loss at high power levels in the kilowatt range that can easily be avoided by connecting a heavy duty electro-mechanical relay (EMR) in parallel with the two solid state relays. The electro mechanical relay (EMR) turns on after a short time delay of about 1 second.
EDIT: I have used this method before.
 
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Lazarus Short

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Is this what this thread is about? I came across this while unpacking a lamp, and it was in the box. i recall that it was in a box of this 'n that at a moving sale where we bought the lot, in March of 2013. I think it's odd that this modern device fits in a tube socket.
 

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#9
That's a standard 8 pin relay socket.. use them by the 100's in the oilfield .......
 

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#11
Is this what this thread is about?
Something similar, but your timer is suitable for applications requiring a wide range of time delays, a much longer time delay and an easily adjustable time delay.
My time delay relay circuit is just a low cost, easy way to achieve a short time delay of only a few seconds, suitable for amplifier de - thump and power supply inrush current limiting applications.

I think it's odd that this modern device fits in a tube socket.
That's a standard 8 pin relay socket.
I have valves / electron tubes and relays at home with this type of plug.
 
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laatsch55

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#12
Yep. Don't know what came over em then. A base that fit more than one type of device.
 

Lazarus Short

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#13
I found the delay relay tubes I mentioned in an earlier post. It looks like the heater warms the bi-metallic strip and brings the contacts together. Anybody want them? The designation is 115N05 or 115NO5, can't tell which. On the box it even tells you how to wire them.
 

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laatsch55

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Those are too fuckin cool!! I also find it hard to tell between an 115NO5 and a 115NO5 myself...
 
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