Wondering if anyone here can help me with a bit of advice .
I have a small electric motor that I have put on a rod turner . The motor is rated for 3v and runs thru a set of gears to reduce the speed at the output shaft .
Works fine at 3 volts but it runs to fast and i need to reduce the voltage to 1.5v to achieve the speed I need . The young "expert" at Jaycar today sold me a resistor to put in the pos lead to the motor to reduce the voltage to 1.5 . Problem is when I soldered the resister inline it let no power thru at all .
The numbers on the resistor are 10w27ohmJ .
Any ideas how I can reduce 3 v to 1.5 ?
Cheers Al
Warren-Pat_01 said
11:51 PM Feb 7, 2018
G'day Al,Will the motor still drive with sufficient torque to turn the rod when it is running with 1.5v?I guess there's one way to find out.
The resistor you were sold is a 27ohm, 10w - obviously too much resistance.
Do you have a multimeter where you can read the resistance of the motor (across the leads)? Then just get an equivalent value resistor & add it in series with your motor.
OR get a LOW resistance wire wound potentiometer (variable resistor) & add it in the circuit - that way you can vary the speed to what is needed.
Swoffer said
12:26 AM Feb 8, 2018
Warren-Pat_01 wrote:
G'day Al,Will the motor still drive with sufficient torque to turn the rod when it is running with 1.5v?I guess there's one way to find out.
The resistor you were sold is a 27ohm, 10w - obviously too much resistance. Do you have a multimeter where you can read the resistance of the motor (across the leads)? Then just get an equivalent value resistor & add it in series with your motor.
OR get a LOW resistance wire wound potentiometer (variable resistor) & add it in the circuit - that way you can vary the speed to what is needed.
DC 1.8V 3V 5V 6V 12V 2A motor speed controller 30W PWM 1803b K7 L6
dorian said
07:55 AM Feb 8, 2018
Would it be possible to redesign the "rod turner" using the 240VAC turntable motor from a discarded microwave oven?
Swoffer said
10:30 AM Feb 8, 2018
dorian wrote:
Would it be possible to redesign the "rod turner" using the 240VAC turntable motor from a discarded microwave oven?
Gday Dorian .
Yeh possibly down the track but I'd like to get it running in this format for now because my old dad (88yo) built it for me this week in his workshop at home , so if its not to expensive I'll keep it as it is for now if I can .
So I've just ordered one of the little PWM controllers off Ebay .
Get this , $1.72 with free postage to Aus , dont know how they do it really , but i'll try it and see .
Cheers Al
T1 Terry said
02:10 PM Feb 8, 2018
woffer wrote:
Warren-Pat_01 wrote:
G'day Al,Will the motor still drive with sufficient torque to turn the rod when it is running with 1.5v?I guess there's one way to find out.
The resistor you were sold is a 27ohm, 10w - obviously too much resistance. Do you have a multimeter where you can read the resistance of the motor (across the leads)? Then just get an equivalent value resistor & add it in series with your motor.
OR get a LOW resistance wire wound potentiometer (variable resistor) & add it in the circuit - that way you can vary the speed to what is needed.
DC 1.8V 3V 5V 6V 12V 2A motor speed controller 30W PWM 1803b K7 L6
These sort of things are great as long as it can pass the start current you need at 1.5v, divide the motor watts by 1.5 to get an idea of how many amps you might need, not a terribly accurate equation but it will give you a guide. Next is to make sure it can actually drop the voltage to 1.5v, the adjustments are not always linear. I used the opposite idea to boost an 18v power tool battery to power a 40v LED flood light using the assumption that if it could boost 12v to 36v then it would easily boost 18v to over 40v ..... you know what they say about assuming :lol: Still the same max voltage of 36v, but fortunately the LED flood light still works fine at that voltage so in this case no harm done. The design aim with the flood light was to make it small and cheap so if it got stolen it wouldn't break the bank.
T1 Terry
dorian said
03:11 PM Feb 8, 2018
Here are the full size images:
As for the LED flood light, ISTM that the booster converter circuit could probably be modified to output 40V instead of 36V by recalculating the value of a feedback resistor. I could help with that, if necessary.
-- Edited by dorian on Thursday 8th of February 2018 03:12:04 PM
T1 Terry said
03:31 PM Feb 8, 2018
Thankyou for the offer Dorian, if it turns out to be a worth while project then I may just take you up on that. The boards themselves are cheap as chips on evilbay so I thought I'd give one a try.
T1 Terry
Warren-Pat_01 said
06:42 PM Feb 8, 2018
Looks good!
Aus-Kiwi said
07:23 PM Feb 8, 2018
Light in series ??
Swoffer said
07:34 PM Feb 8, 2018
Aus-Kiwi wrote:
Light in series ??
Sorry ?
Swoffer said
07:36 PM Feb 8, 2018
Warren-Pat_01 wrote:
Looks good!
Thanks
hako said
09:23 PM Feb 8, 2018
You could try using rechargeable batteries which are 1.2v each so 2 = 2.4v.
Swoffer said
09:29 PM Feb 8, 2018
hako wrote:
You could try using rechargeable batteries which are 1.2v each so 2 = 2.4v.
Yeh thats an option Dennis . I'll try this little hoodjigger from China first and see .
sandman55 said
09:17 PM Feb 10, 2018
We don't know what current the motor draws, if you try the variable resistor idea and it (the vairable resistor) gets warm then you need to increase the wattage. As someone said I wonder if the motor will have enough torque at 1.5 volts. What are you using as a power supply. If you want to try it out you could get some "D" cell batteries and depending on the size of the motor to keep the batteries at 1.5 volts but increase the capacity connect the positives of the batteries together and the negatives together that way you will get more current but maintain 1.5 volts. You will then see how it runs and if it has enough torque and see if the motor gets hot. Another way is get another resistor the same from Jaycar and put the two in parallel (side by side) that way you will halve the resistance three in parallel will give you one third of the resistance.
-- Edited by sandman55 on Saturday 10th of February 2018 09:18:08 PM
-- Edited by sandman55 on Saturday 10th of February 2018 09:23:37 PM
Hi all ,
Wondering if anyone here can help me with a bit of advice .
I have a small electric motor that I have put on a rod turner . The motor is rated for 3v and runs thru a set of gears to reduce the speed at the output shaft .
Works fine at 3 volts but it runs to fast and i need to reduce the voltage to 1.5v to achieve the speed I need . The young "expert" at Jaycar today sold me a resistor to put in the pos lead to the motor to reduce the voltage to 1.5 . Problem is when I soldered the resister inline it let no power thru at all .
The numbers on the resistor are 10w27ohmJ .
Any ideas how I can reduce 3 v to 1.5 ?
Cheers Al
The resistor you were sold is a 27ohm, 10w - obviously too much resistance.
Do you have a multimeter where you can read the resistance of the motor (across the leads)? Then just get an equivalent value resistor & add it in series with your motor.
OR get a LOW resistance wire wound potentiometer (variable resistor) & add it in the circuit - that way you can vary the speed to what is needed.
Like something like this from Ebay for instance ?
DC 1.8V 3V 5V 6V 12V 2A motor speed controller 30W PWM 1803b K7 L6
Gday Dorian .
Yeh possibly down the track but I'd like to get it running in this format for now because my old dad (88yo) built it for me this week in his workshop at home , so if its not to expensive I'll keep it as it is for now if I can .
So I've just ordered one of the little PWM controllers off Ebay .
Get this , $1.72 with free postage to Aus , dont know how they do it really , but i'll try it and see .
Cheers Al
These sort of things are great as long as it can pass the start current you need at 1.5v, divide the motor watts by 1.5 to get an idea of how many amps you might need, not a terribly accurate equation but it will give you a guide. Next is to make sure it can actually drop the voltage to 1.5v, the adjustments are not always linear. I used the opposite idea to boost an 18v power tool battery to power a 40v LED flood light using the assumption that if it could boost 12v to 36v then it would easily boost 18v to over 40v ..... you know what they say about assuming :lol: Still the same max voltage of 36v, but fortunately the LED flood light still works fine at that voltage so in this case no harm done. The design aim with the flood light was to make it small and cheap so if it got stolen it wouldn't break the bank.
T1 Terry
Here are the full size images:
As for the LED flood light, ISTM that the booster converter circuit could probably be modified to output 40V instead of 36V by recalculating the value of a feedback resistor. I could help with that, if necessary.
-- Edited by dorian on Thursday 8th of February 2018 03:12:04 PM
T1 Terry
Sorry ?
Thanks
Yeh thats an option Dennis . I'll try this little hoodjigger from China first and see .
We don't know what current the motor draws, if you try the variable resistor idea and it (the vairable resistor) gets warm then you need to increase the wattage. As someone said I wonder if the motor will have enough torque at 1.5 volts. What are you using as a power supply. If you want to try it out you could get some "D" cell batteries and depending on the size of the motor to keep the batteries at 1.5 volts but increase the capacity connect the positives of the batteries together and the negatives together that way you will get more current but maintain 1.5 volts. You will then see how it runs and if it has enough torque and see if the motor gets hot. Another way is get another resistor the same from Jaycar and put the two in parallel (side by side) that way you will halve the resistance three in parallel will give you one third of the resistance.
-- Edited by sandman55 on Saturday 10th of February 2018 09:18:08 PM
-- Edited by sandman55 on Saturday 10th of February 2018 09:23:37 PM