Transistor as Relay Setup: Tips for Quicker Circuit Release

[462chevelle]

I'm looking for some help setting up a circuit system. Were currently using a magnetic type trigger relay. I am trying to get a quicker release of the circuit. Its for the trans brakes on our drag cars.
Here is what i was thinking, this is of course a very rough and first draft of my thoughts. I am not sure how transistors work or what kind of problems i would have doing this but I am willing to learn.

 

[davenn]

hi there

not quite drawn like that but a close attempt

before a suitable transistor could be suggested, we would need to know the current in Amps that the solenoid requires to be operated. as the transistor would have to switch this amount of current

cheers
Dave

 

[462chevelle]

Ya, my paint drawing skills suck, but you get the idea i guess. No more than 10 amps, some solenoids pull 1-2 some pull 5-6. 12 volt systems. The solenoid will be triggered for no longer than 10 seconds at a time, since with a couple types of trans brakes. You have to use the brake for reverse. Though i would like the circuit to be able to handle 20 amps at a minimum.

 

[jim hardy]

Were currently using a magnetic type trigger relay. I am trying to get a quicker release of the circuit.

I gather there's a noticeable delay now between operating your switch and the actual solenoid release?

Help the folks here help you...

two questions that'll help get you an optimal fix:

1. Is there a datasheet or part number for the relay, and one for the brake ?

It's possible that your delay is in the brake solenoid itself.
If it is equipped with a "flywheel diode" to protect your mechanical relay or switch contact from arcing ,
a faster electronic relay would still have to wait while the solenoid's coil discharges into that protective flywheel diode.
Might be that just a tweak of that protective circuit would do the trick for you.

2. Do you have access to the solenoid's ground wire?

Sometimes it's easier to place an electronic switch in that wire than in the "hot" one..

old jim

 

[alphy]

I would highly recommend considering using a solid-state relay (SSR) instead of a magnetic trigger relay for your circuit system. SSRs use transistors to switch on and off the circuit, providing a much faster response time compared to magnetic relays.

To set up your circuit with an SSR, you will need to connect the control signal from your trans brake to the input of the SSR, and the output of the SSR to the circuit that controls the brake. This will allow the SSR to quickly switch on and off the circuit, providing a quicker release for the trans brake.

One potential issue you may face with using transistors is their sensitivity to heat. Make sure to choose transistors with a high enough power rating to handle the current and voltage requirements of your circuit, and consider using heat sinks to dissipate any excess heat.

Additionally, it is important to consider the type of transistor you use. Bipolar junction transistors (BJTs) and field-effect transistors (FETs) have different characteristics and may be more suitable for different applications. It is important to research and understand the differences between these types of transistors to choose the best one for your circuit.

Overall, using transistors in your circuit setup can provide a faster and more efficient response compared to magnetic relays. However, it is important to carefully research and understand how transistors work and their limitations in order to successfully implement them in your circuit. I wish you luck in your project and am happy to assist with any further questions you may have.