Can I Use a H bridge to open and close actuator?

Thread Starter

ngwpower

Joined Oct 2, 2014
7
Have the parts just do not know how to convert 12V from 110V and dumb as a rock with electricity. Not sure what I need to use a H bridge, if one would work.upload_2014-10-2_11-33-3.png
 

mcgyvr

Joined Oct 15, 2009
5,394
You need more than one device there...

A double throw relay (form C) will work just fine with a 12V power supply.. One with a 120VAC coil and then use the contacts to switch polarities
An H bridge can be used too but its job is NOT to convert voltage and will still require a power supply..

Its a AC/DC adapter that converts AC voltage to DC voltage..
Commonly called a DC power supply or "wall-wart" or DC adapter,etc..

Then does your actuator have limit switches built in?
 

MikeML

Joined Oct 2, 2009
5,444
Your grey box just puts out 120V when a set of conditions exist, and no voltage when that set of conditions dont exist.

To run the actuator out you need a DC voltage of +- polarity. To run the actuator in you need a DC voltage of the -+ (opposite) polarity. Depending on the actuator, these voltages can be applied either continuously, or not (be timed).
'
I recently bought an actuator that looks like the one in your picture, and it has built-in limit switches which allow you to keep applying 12Vdc indefinitely, until the polarity is reversed.

As suggested, a 120Vac coil DPDT (Form C) relay will do the reversing. Here is how to hook it up:


ps: The relay is wired as a "H-Bridge"

212.jpg
 
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MaxHeadRoom

Joined Jul 18, 2013
30,654
Have you checked if in fact that there is no alternative to the 120v output? I am assuming the unit is switching the 120vac with a relay? If it is, there may be an option of removing the 120vac and use the internal relay to switch the actuator L.V. DC direct?
Max.
 

Thread Starter

ngwpower

Joined Oct 2, 2014
7
Never looked Max I usually don't open electrical products if they are not broke, so will check.
Thanks RJ
 

MaxHeadRoom

Joined Jul 18, 2013
30,654
Appears to be four relays operating four AC outlets, but it should be simple to swap any one of them to switch and voltage or device you what to.
Max.
 

Thread Starter

ngwpower

Joined Oct 2, 2014
7
Thank you for the diagram and instructions. Wired it up like you show and can hear the solenoid activate, hear the temperature sensor actuate. The actuator will run in one direction according to which lead is hooked up to 7 and 9; using a 12VDC battery. I dropped the DPDT in my shop, could I have damaged the internal components? Have the worst luck with electrical anything.
RJ
 

MikeML

Joined Oct 2, 2009
5,444
Connect the two actuator wires directly to the terminals of the 12Vdc power supply; first red to +, and black to -, actuator should run one way and stop. The reverse red and black at the power supply terminals; it should run the other way and stop.


If actuator runs as described above, the problem is in the wiring or the relay...
If the actuator runs only one way even after swapping the leads at the power supply, then post the data sheet for the actuator, or the power supply is inadequate.

Do you own a Multi-Meter?
 
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MikeML

Joined Oct 2, 2009
5,444
I dont see problem with the relay. The Ohmmeter test looks good.
I dont see a prob. with the 120V to the relay coil.
I dont understand the reading at the actuator. There should always be 12Vdc across the actuator; with relay not pulled in, polarity should be one way, with the relay pulled in, the polarity should reverse...

Where did you have the Multimeter leads to measure the actuator voltage? Directly between red and black?
 
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Thread Starter

ngwpower

Joined Oct 2, 2014
7
"Where did you have the Multimeter leads to measure the actuator voltage? Directly between red and black?" yes.
How about the gray box? Put the meter on the outlet for thermostat and below set temperature I get power; when I warm up the probe above set temperature I get no power at AC V. Probably wrong but this appears to be why this is not working?
RJ
 

MikeML

Joined Oct 2, 2009
5,444
...
How about the gray box? Put the meter on the outlet for thermostat and below set temperature I get power; when I warm up the probe above set temperature I get no power at AC V. Probably wrong but this appears to be why this is not working?
Read the first sentence in my post #3 in this forum thread...

btw-these postings are coming from a rented beach house near Hilo, HI...
 
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