solenoid driver circuit help

Thread Starter

minkey01

Joined Jul 23, 2014
185
could you draw in the isolation transformer and fuse in the circuit please? also their part number or ratings?

then i could try this thing out.

thanks!!
 

Thread Starter

minkey01

Joined Jul 23, 2014
185
anyone?

isolation transformer part # please?

fuse part # please?

for this full wave bridge application. i'd like to try it soon.

thank you!
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
You can obtain a 240/120 to 120 isolation transformer from any Electrical supplier in your area, the capacitor could be 20μ-50μ 200v if needed.
probably 1/2amp fuse on both primary and secondary, if you leave the secondary ungrounded, then normally you should fuse both leads of the secondary.
Max.
 

Thread Starter

minkey01

Joined Jul 23, 2014
185
Mr HeadRoom - Can you tell which terminals on my new isolation transformer go to the wall ac and which ones go to the solenoid circuit?

Last question, I swear. ;)

Thank you so much!!
 

SgtWookie

Joined Jul 17, 2007
22,230
If a cap is used across the output of the rectifier bridge, then the DC out will be closer to 170 VDC instead of ~120 VDC; the solenoid will be operating at nearly twice its rated voltage. That will lead to early failure of the solenoid.
 

Thread Starter

minkey01

Joined Jul 23, 2014
185
thanks wookie! i'll remove cap and measure voltage to make sure i don't wear this thing out.

i also have this optional circuit shown in the picture. dont think its a rectifier like the other suggestions. what do you guys think about this one and how would it compare to the rectifier circuit options?
 

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alfacliff

Joined Dec 13, 2013
2,458
in the origional post, he said the solenooid is rated for 100 volts and the supply is 75, how would that cause overheating? the reduce current after pull in is used for when a solenoid is ran at or above its rated voltage.
 

inwo

Joined Nov 7, 2013
2,419
I would put the switch between the cap and solenoid.

Then move the resistor to a position before the cap.
 

Johann

Joined Nov 27, 2006
190
in the origional post, he said the solenooid is rated for 100 volts and the supply is 75, how would that cause overheating? the reduce current after pull in is used for when a solenoid is ran at or above its rated voltage.
This means he can use full-wave rectifier and smoothing capacitor. 75V/0.707 = 106V roughly and subtracting the forward volt drops of two diodes per half cycle, will theoretically subject the coil to approx. 105V which should not overheat the coil.
 
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