I want to control the mains power to a repurposed power drill - around 600W on 220V AC
I have a few spare Fotek SSRs for AC, 20amp and some 40amp models ( copies - not original Fotek ).
Ideally I want to use a foot pedal, so was thinking to :
Use a standard wall mount type PVC 4x4 box to hold a 5VDC supply and the SSR.
Connect the +5VDC to the SSR input DC Positive terminal
3D print a foot pedal that contains a micro switch.
Connect the the wires from the foot pedal to the power supply Ground, and to the SSR DC Input ground - so pressing the foot pedal closes the microswitch, which energises the SSR
Connect the Live / Hot for the power drill thru the AC terminals on the SSR
Add a 100K resistor over the SSR Input / Control terminals to pull the wire ( from the micro switch ) HIGH, until the foot pedal is pressed.
Is there any reason this should not work ?
Does the fact that I want to control a power drill have any adverse effect on the SSR during power on or power off ?
Yeah, I already did that. Big surprise, you can't control the speed. You need a AC PHASE CONTROLLER (dimmer)
to do that. The SSR will just give it full power .
raschemmel:
Yeah, I already did that. Big surprise, you can't control the speed. You need a AC PHASE CONTROLLER (dimmer)
to do that. The SSR will just give it full power .
Thanks. The power drill has it's own speed control on the trigger. I just need to turn it on / off with the foot pedal.
Thanks for the reply.
To answer your question.
Let Vcc = 5V
R = 100,000
I = 5/100000
I = 0.000050A
which, one would assume , you know is 50uA
Given that anyone who has ever come in contact with electronics knows that an led be it visible 5mm red led
or an opto-coupler led is going to draw 10mA to 30mA , and average about 20mA.
Given that the circuit you describe will deliver a current 400 times smaller than required, I think it is safe to say,
"No", it would not work.
"What to do ?"
Remove the resistor and connect the DC + TERMINAL directly to 5V.
Closing the pedal completes the circuit
by connecting the SSR led cathode to GND, drawing current (pulling the dc + terminal high with an open circuit would not have any effect. putting the 100k resistor in parallel with the dc input terminals would also have no effect because the led
wouldn't light)
raschemmel:
Remove the resistor and connect the DC + TERMINAL directly to 5V.
Closing the pedal completes the circuit
by connecting the SSR led cathode to GND, drawing current (pulling the dc + terminal high with an open circuit would not have any effect. putting the 100k resistor in parallel with the dc input terminals would also have no effect because the led
wouldn't light)
so the pull up resistor is not needed ?
Would the fact that, when the pedal switch is open, the wire from the switch, to the Input Negative on the SSR is floating ? Could that not be affected by interference in any way ?
Just trying to ensure it is as safe as possible for the project ( own use only )
An SSR contains an internal resistor. It is designed to be connected directly to 3C - 24V (sometimes 36V)
Connecting the + terminal to 5V and leaving the - terminal open creates an open circuit. No component
is relevant in an open circuit. Just ground the - terminal with the pedal.
PerryBebbington:
I'm not clear what the SSR and all the other stuff is for; if you just want to turn it on and off what is wrong with a switch?
It is a respooler for 3D print filament ( making sure the filament is good before starting to print with a spool ), so both hands will be busy, and want to control the drill, which drives the respooler, with a foot pedal.
Ok....?
I still don't understand why you need the SSR and all the other stuff. What is wrong with a foot pedal containing a suitable mechanical switch?
PerryBebbington:
Ok....?
I still don't understand why you need the SSR and all the other stuff. What is wrong with a foot pedal containing a suitable mechanical switch?
ok.
A few reasons ..
we live in Africa and getting spares and parts here is not the easiest of things.
they also cost money which I am trying to not spend at the moment.
it is used outdoors and sometimes the ground could be damp - don't want 220V under my foot on damp ground.
I have a 3D printed footpedal complete with a micro switch
I already have a few spare SSRs in my box of bits.
I really do appreciate everyones input. Please don't think that I am not open to ideas ( like using / buying another foot pedal ).
I am looking to :
re-purpose things that I already have, and
avoid spending / buying new parts when existing parts can acheive the same end goal
I have the parts, but just needed to make 100% sure that they are suitable for the task. They don't have to be the 'best' solution - just need to reach the intended goal
