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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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 15 Nov 2006 6:56 Dual Voltage DC Motor |
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| Dear guys!!! On a 12V DC miniature motor,can I add a zener diode in series on +VE (or maybe -VE) to run at 24V DC without affect its current? Any suggestion?
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IanP
Joined: 05 Oct 2004
Posts: 6346
Helped: 1505
Location: West Coast
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| 15 Nov 2006 8:48 Re: Dual Voltage DC Motor |
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If Zener diode is rated for higher current than the motor - you can ..
If not, you can implement Zener follower .. see picture below ..
In both cases you have to be aware of possible heat generation ..
Regards,
IanP
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 15 Nov 2006 14:11 Dual Voltage DC Motor |
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Dear IanP,
The DC motor will generate around 50mA(at)12V DC,
what's the zener diode,resistor & transistor value should I use according to yr ideals?
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IanP
Joined: 05 Oct 2004
Posts: 6346
Helped: 1505
Location: West Coast
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| 16 Nov 2006 2:28 Re: Dual Voltage DC Motor |
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For 12V output you need 13V zener diode (500mW), as R you can use 1kΩ and transistor can be of almost any type (Ic>500mA), something like 2N2222 (N100, BC337, BC639, BD135, ..) will do ..
Rc<100Ω (0.5W) or not used at all ..
Regards,
IanP
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 16 Nov 2006 3:42 Dual Voltage DC Motor |
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ok,I got BC546B transistor, should be no problems?
Assuming 24V go into Vin, GND means -VE rite? Vout = 12V?
Thanks!
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IanP
Joined: 05 Oct 2004
Posts: 6346
Helped: 1505
Location: West Coast
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| 16 Nov 2006 3:52 Re: Dual Voltage DC Motor |
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BC546 is rated only for Ic< 100mA but in motor applications you should really look for something rated for higher current ..
| Quote: |
| Assuming 24V go into Vin, GND means -VE rite? Vout = 12V? |
Correct ..
Regards,
IanP
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 16 Nov 2006 5:41 Dual Voltage DC Motor |
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ok, I'll look for higher current transistor
Added after 1 hours 28 minutes:
or can I exclude the transistor?
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 17 Nov 2006 4:35 Dual Voltage DC Motor |
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| can I exclude the transistor?
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IanP
Joined: 05 Oct 2004
Posts: 6346
Helped: 1505
Location: West Coast
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| 17 Nov 2006 5:10 Re: Dual Voltage DC Motor |
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If your motor doesn't draw more than 50mA you can try to use only 12V zener diode, but make sure that it is rated for at least 1W ..
Regards,
IanP
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 18 Nov 2006 14:01 Dual Voltage DC Motor |
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| can it run continously for atleast 3 days?
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 20 Nov 2006 7:30 Dual Voltage DC Motor |
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Can I wire like this with 1w12V zener diode?
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IanP
Joined: 05 Oct 2004
Posts: 6346
Helped: 1505
Location: West Coast
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| 20 Nov 2006 8:30 Re: Dual Voltage DC Motor |
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You need to use the zener voltage (12V) and not the forward voltage (0.7V) ..
Connect the 12V zener diode the opposite way around (cathode to 24V) and it should work ..
Regards,
IanP
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 21 Nov 2006 14:58 Dual Voltage DC Motor |
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Like This?
Added after 38 minutes:
Whats the defference between the above & this wiring?
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 04 Dec 2006 8:42 Dual Voltage DC Motor |
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| will the 2nd wiring work also?
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manish12
Joined: 21 Nov 2006
Posts: 955
Helped: 29
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| 06 Dec 2006 18:03 Re: Dual Voltage DC Motor |
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| dod you know at the start of power supply motor take nearly 800ma - 1a.?
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 07 Dec 2006 1:31 Dual Voltage DC Motor |
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| my motor won't take tat high current,beow 100mA on starting...
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VSMVDD
Joined: 12 Jun 2005
Posts: 567
Helped: 55
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| 07 Dec 2006 2:27 Re: Dual Voltage DC Motor |
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use 2 X 6volts zeners
500 mw zeners is all thats needed at 12 volts
or ~ this value for a 1 amp standing current
maybe also add a 12v clamp zener on the + rail
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me_guitarist
Joined: 03 Oct 2006
Posts: 152
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| 08 Dec 2006 2:46 Dual Voltage DC Motor |
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| 2 x 6V zemers in series or parallel?my motor only need 50mA(at)24V DC
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