I was assigned a project that requires the automation of an electric hoist purchased from Ironton. The hoist includes a controller with a rocker switch (DPDT) for the user to push up/down to lift/let down an object. I have decided to use an Arduino Uno to "hack" the controller so that the hoist will be activated at different time intervals specified by the Arduino.
The only difference is that my electric hoist's lift capacity is 110lb compared to the reference's lift capacity of > 1000 lb. Their system came with two capacitors with equal values of 80uF. I only have one capacitor with a value of 25uF. I am wondering how to determine what resistor value to put in parallel with my capacitor to ensure it discharges fully without damage or defects.
This is the circuit for the discharge of the capacitor:
Thank you very much! Feel free to share your opinion on this solution to my project prompt.
pearc1jj:
I was assigned a project that requires the automation of an electric hoist purchased from Ironton. The hoist includes a controller with a rocker switch (DPDT) for the user to push up/down to lift/let down an object. I have decided to use an Arduino Uno to "hack" the controller so that the hoist will be activated at different time intervals specified by the Arduino.
The only difference is that my electric hoist's lift capacity is 110lb compared to the reference's lift capacity of > 1000 lb. Their system came with two capacitors with equal values of 80uF. I only have one capacitor with a value of 25uF. I am wondering how to determine what resistor value to put in parallel with my capacitor to ensure it discharges fully without damage or defects.
This is the circuit for the discharge of the capacitor:
Thank you very much! Feel free to share your opinion on this solution to my project prompt.
You need to do some more investigation. The control is a DPDT center off switch. Nothing more!
Look at the capacitors!!!! They are AC rated because the motor is a split phase AC motor and needs one capacitor between the hot power and the third wire to the motor for each direction.
To automate your lift, you need two DPST relays to replace the manual switch. They CAN'T be the cheap Chinese relays from Ebay. They will need to be controllable from the Arduino.
Paul
edit: You need to keep the capacitors and use them exactly are is currently being done. You are only replacing the switch with the relays.
Paul, Do you think two of these DPST relay will be adequate?
The ratings of the controller's center off switch are
20A 125VAC
15A 250V~
15A 250V~
Yes, the motor is 0.17hp., pretty small, but they have 12 volt dc coils, so you will need a 12 volt supply and a mosfet circuit to control them with a 5 volt Arduino.
Are you making a printed circuit board to hold the relays, and other parts?
Thank you so much Paul! I'm using a breadboard per request of my teacher.
Would the MOSFET circuit look something like attached schematic? Also do I choose a transistor with a drain current about equal to the coil current of the DPST relay?
