P
Phil Allison
Guest
"Tom is Biasically Wrong"
.... Phil
** Last 5 seconds - if he were lucky.
.... Phil
P
Phil Allison
Guest
"DJ Delorie"
** None of the relevant to the OP's query.
...... Phil
** None of the relevant to the OP's query.
...... Phil
P
Phil Allison
Guest
"David Eather"
** Absolutely correct.
** The item on eBay is junk.
The OP has no idea what specs he really needs.
...... Phil
** Absolutely correct.
** The item on eBay is junk.
The OP has no idea what specs he really needs.
...... Phil
P
Phil Allison
Guest
"DJ Delorie"
** No DC motor benefits from high frequency PWM.
The practical range is from a few hundred Hz to a few kHz ONLY.
..... Phil
** No DC motor benefits from high frequency PWM.
The practical range is from a few hundred Hz to a few kHz ONLY.
..... Phil
P
Phil Allison
Guest
"DJ Delorie"
** Don't you ever get sick of posting BS ?
... Phil
<dj@delorie.com> wrote in message news:xnfxb74mgb.fsf@delorie.com...
** Don't you ever get sick of posting BS ?
... Phil
<dj@delorie.com> wrote in message news:xnfxb74mgb.fsf@delorie.com...
P
Phil Allison
Guest
"Tom is Biasically Wrong"
** Like 50 to 100 amps.
...... Phil
** Like 50 to 100 amps.
...... Phil
T
Tom Biasi
Guest
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7g3frbF2lossbU1@mid.individual.net...
Tom
news:7g3frbF2lossbU1@mid.individual.net...
Did you test one?
Tom
A
amdx
Guest
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7g3g2tF2nt4amU1@mid.individual.net...
from the motor low.
Mike
news:7g3g2tF2nt4amU1@mid.individual.net...
between 15Khz and 20 Khz. I think that is to keep the audio
from the motor low.
Mike
P
Phil Allison
Guest
"Tom is Biasically Wrong"
** Cos I have lots of actual experience with such devices and YOU have none.
FUCKWIT
...... Phil
** Cos I have lots of actual experience with such devices and YOU have none.
FUCKWIT
...... Phil
T
Tom Biasi
Guest
"gearhead" <nospam@billburg.com> wrote in message
news:e83131a1-1c18-4f5c-b42d-21e8ca74f362@f33g2000vbm.googlegroups.com...
On Aug 31, 10:48 pm, "Tom Biasi" <tombi...@optonline.net> wrote:
The thing is only rated for 15 amps.
Also, there's a question at the bottom of that item from somebody
that wants to use the controller on an electric bike.
Seller says no, can't use it for that.
The OP said he needed 10-15 amps. I didn't suggest he buy it, I just said
before you build, look here. There has to be at least $20.00 worth of parts
in it.
Tom
news:e83131a1-1c18-4f5c-b42d-21e8ca74f362@f33g2000vbm.googlegroups.com...
On Aug 31, 10:48 pm, "Tom Biasi" <tombi...@optonline.net> wrote:
Don't get him started. Anyway, he's right.
The thing is only rated for 15 amps.
Also, there's a question at the bottom of that item from somebody
that wants to use the controller on an electric bike.
Seller says no, can't use it for that.
The OP said he needed 10-15 amps. I didn't suggest he buy it, I just said
before you build, look here. There has to be at least $20.00 worth of parts
in it.
Tom
P
Phil Allison
Guest
"Tom is Biasically Wrong"
** The OP is a clueless jerk.
Will self destruct in milliseconds with a stalled motor.
...... Phil
** The OP is a clueless jerk.
** Same thing - FUCKWIT !!
** One 15amp MOSFET, one 555, a cheap pot and a box.
Will self destruct in milliseconds with a stalled motor.
...... Phil
T
Tom Biasi
Guest
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7g3hbeF2k078aU1@mid.individual.net...
news:7g3hbeF2k078aU1@mid.individual.net...
Tom
P
Phil Allison
Guest
"Tom is Biasically Wrong"
** Easy to tell YOU have NONE.
You spew STUPID and WRONG advice all the time.
BTW
You have "eperience " all right.
Everything you spew is stolen from the " enet " .
...... Phil
** Easy to tell YOU have NONE.
You spew STUPID and WRONG advice all the time.
BTW
You have "eperience " all right.
Everything you spew is stolen from the " enet " .
...... Phil
T
Tom Biasi
Guest
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7g3i38F2904c9U1@mid.individual.net...
news:7g3i38F2904c9U1@mid.individual.net...
M
Michael
Guest
On Aug 31, 6:16 pm, George Herold <ggher...@gmail.com> wrote:
Learning, yep. Otherwise I would just plunk down a few hundred bucks
and get a genuine Fischer-Price vehicle.
Thanks,
Michael
On Aug 31, 3:57 pm, Michael <mrdarr...@gmail.com> wrote:
On Aug 31, 12:49 pm, George Herold <ggher...@gmail.com> wrote:
On Aug 31, 2:43 pm, Michael <mrdarr...@gmail.com> wrote:
I've got an electric car for the kids that has only an On-Off switch
for speed control. I was hoping to add a better speed controller than
that. I would need to PWM 12V, about 10-15A. I was hoping to use a
555 to generate the pulses to the mosfet gates.
I saw this:http://zeva.com.au/speedy/
I can appreciate the beefy freewheel diode and mosfets, but would I
really need a FET driver? At what point do I need a FET driver?
Would the output from a 555 suffice?
Thanks,
Michael
Is it one of the small 'power wheels'? (that is the fisher-price name
though there are other manufacturers.) With two small gel cel lead
acid batteries?
If so you can add a simple speed control by putting 'about' a 1/2 ohm
resistor is series with the battery. But I found that after a few
trips the kids want to drive it 'full on' all the time.
George H.
Nope, got it at a flea market. Originally runs on 6V, but that didn't
give a whole lot of power (step on the throttle, and nada). Put in a
higher A-h 6V battery, and works a little better, but still not much
power. Put in a 12V battery from a different project, and whoa, yee-
haw! A bit too much power. Wires got hot, too. So I'm planning on
re-doing the wiring, and adding a PWM control. Maybe a fan, but if I
do that, would that just fan the flames...?
I'm still annoyed that the original 6V battery charger that came with
it gave 8+ volts output across the battery terminals after charging
overnight. I shouldn't have trusted them, but hey... I gave them the
benefit of the doubt. Now I use a dedicated 6/12V adjustable Pb-acid
battery charger.
Right now it's just sitting in the room, no one riding it, because the
6V battery (even the bigger one) doesn't give enough juice. A pity.
Michael- Hide quoted text -
- Show quoted text -
Hmm, I'm not much of an expert, but I would think that you might end
up frying the motors if you push to much current through them.
They're probably designed to run with the series resistance of the
battery to limit the current. (What's the 6V battery voltage when the
it's putting out 10 or 15 amps?) But if you don't mind wasting the
power a resistor in series with your 12V battery may do the trick.
Unless you are just wanting to learn about PWM circuits and all.
George H.
Learning, yep. Otherwise I would just plunk down a few hundred bucks
and get a genuine Fischer-Price vehicle.
Thanks,
Michael
P
Phil Allison
Guest
"gearhead"
I read through most of the posts. I'll endorse those who made
statements to the effect that the drive frequency for a motor is so
low that a 555 will do just fine. You can run it around 1kHz,
ballpark, but anything from 100Hz to 10kHz would probably work.
I'd choose 400 Hz myself. Don't forget the freewheel diode.
A power Schottky is a good choice for this.
You can get the gearshift effect with a switch that has multiple taps
connected to a resistor network. That ought to be really fun. Use
12 volts, but have the top speed something less than 100%.
Experiment to find the best "governor" frequency.
The usual way of hooking up a 555 astable gives duty cycles only
between 50% and 100%, nothing less than 50%.
You can give it a full range of duty cycle by putting a diode across
pins 6 and 7 with the cathode at pin 6.
** The best arrangement is the one shown here.
http://adibakri.co.cc/wp-content/uploads/2008/06/pwm-with-555-electronic-circuit.gif
C1 could be changed to 0.022 with advantage.
The OP will need about 4 x BUZ11s in parallel to be safe and use a 15 or 20
amp thermal breaker in the battery line
...... Phil
I read through most of the posts. I'll endorse those who made
statements to the effect that the drive frequency for a motor is so
low that a 555 will do just fine. You can run it around 1kHz,
ballpark, but anything from 100Hz to 10kHz would probably work.
I'd choose 400 Hz myself. Don't forget the freewheel diode.
A power Schottky is a good choice for this.
You can get the gearshift effect with a switch that has multiple taps
connected to a resistor network. That ought to be really fun. Use
12 volts, but have the top speed something less than 100%.
Experiment to find the best "governor" frequency.
The usual way of hooking up a 555 astable gives duty cycles only
between 50% and 100%, nothing less than 50%.
You can give it a full range of duty cycle by putting a diode across
pins 6 and 7 with the cathode at pin 6.
** The best arrangement is the one shown here.
http://adibakri.co.cc/wp-content/uploads/2008/06/pwm-with-555-electronic-circuit.gif
C1 could be changed to 0.022 with advantage.
The OP will need about 4 x BUZ11s in parallel to be safe and use a 15 or 20
amp thermal breaker in the battery line
...... Phil
G
gearhead
Guest
On Aug 31, 10:48 pm, "Tom Biasi" <tombi...@optonline.net> wrote:
The thing is only rated for 15 amps.
Also, there's a question at the bottom of that item from somebody
that wants to use the controller on an electric bike.
Seller says no, can't use it for that.
Don't get him started. Anyway, he's right.
The thing is only rated for 15 amps.
Also, there's a question at the bottom of that item from somebody
that wants to use the controller on an electric bike.
Seller says no, can't use it for that.
G
gearhead
Guest
On Aug 31, 2:43 pm, Michael <mrdarr...@gmail.com> wrote:
I'll have to use google:
I read through most of the posts. I'll endorse those who made
statements
to the effect that the drive frequency for a motor is so low that a
555 will
do just fine. You can run it around 1kHz, ballpark, but anything from
100Hz
to 10kHz would probably work. I'd choose 400 Hz myself. Don't forget
the freewheel diode. A power Schottky is a good choice for this.
You can get the gearshift effect with a switch that has multiple taps
connected
to a resistor network. That ought to be really fun. Use 12 volts,
but have
the top speed something less than 100%. Experiment to find the best
"governor" frequency.
The usual way of hooking up a 555 astable gives duty cycles only
between 50%
and 100%, nothing less than 50%.
You can give it a full range of duty cycle by putting a diode across
pins 6 and 7
with the cathode at pin 6. Then it will get down to zero, or almost.
If you want continuously variable with a pot, tie one end of the pot
to pin 6,
the wiper to pin 7. Just a reminder, you still want a little signal
diode like a
1N4148 as I mentioned across 6 and 7. The other end gets connected to
a
resistor, and the other end of that resistor
gets connected to pin 8. The reason you don't tie the pot directly to
pin 8
is because if you turn the pot all the way to the end then it will
short Vcc to
ground when pin 7 discharges. The 1k resistor prevents that.
The pot should be an order of magnitude or greater than the protection
resistor, so you're looking at a 10k or 100k pot. Do your frequency
calculations and choose the timing cap accordingly.
Don't forget basics like a 0.1 bypass cap on the pins of the 555,
especially if you use the bipolar version.
I don't have a mosfet on the tip of my typing fingers to suggest, but
you can use digikey's parametric search. click on site map--part
search--
discretes--mosfets. Get N channel with I guess 100 or 150 volts Vds.
No need for a logic level device if you are using 12 volts, just get a
standard mosfet. Choose Rds by figuring out how much power it will
dissipate at 15 amps. Actually, if your kids stall it and keep the
throttle
down it could draw a lot more than that for a good ten seconds. Stuff
happens. So build in a big safety margin.
Make sure either that the heatsink is electrically insulated, or the
mosfet
is insulated from the heatsink.
I tried to post this under my usenet account but it didn't work, so
I'll have to use google:
I read through most of the posts. I'll endorse those who made
statements
to the effect that the drive frequency for a motor is so low that a
555 will
do just fine. You can run it around 1kHz, ballpark, but anything from
100Hz
to 10kHz would probably work. I'd choose 400 Hz myself. Don't forget
the freewheel diode. A power Schottky is a good choice for this.
You can get the gearshift effect with a switch that has multiple taps
connected
to a resistor network. That ought to be really fun. Use 12 volts,
but have
the top speed something less than 100%. Experiment to find the best
"governor" frequency.
The usual way of hooking up a 555 astable gives duty cycles only
between 50%
and 100%, nothing less than 50%.
You can give it a full range of duty cycle by putting a diode across
pins 6 and 7
with the cathode at pin 6. Then it will get down to zero, or almost.
If you want continuously variable with a pot, tie one end of the pot
to pin 6,
the wiper to pin 7. Just a reminder, you still want a little signal
diode like a
1N4148 as I mentioned across 6 and 7. The other end gets connected to
a
resistor, and the other end of that resistor
gets connected to pin 8. The reason you don't tie the pot directly to
pin 8
is because if you turn the pot all the way to the end then it will
short Vcc to
ground when pin 7 discharges. The 1k resistor prevents that.
The pot should be an order of magnitude or greater than the protection
resistor, so you're looking at a 10k or 100k pot. Do your frequency
calculations and choose the timing cap accordingly.
Don't forget basics like a 0.1 bypass cap on the pins of the 555,
especially if you use the bipolar version.
I don't have a mosfet on the tip of my typing fingers to suggest, but
you can use digikey's parametric search. click on site map--part
search--
discretes--mosfets. Get N channel with I guess 100 or 150 volts Vds.
No need for a logic level device if you are using 12 volts, just get a
standard mosfet. Choose Rds by figuring out how much power it will
dissipate at 15 amps. Actually, if your kids stall it and keep the
throttle
down it could draw a lot more than that for a good ten seconds. Stuff
happens. So build in a big safety margin.
Make sure either that the heatsink is electrically insulated, or the
mosfet
is insulated from the heatsink.
G
gearhead
Guest
On Aug 31, 11:37 pm, gearhead <nos...@billburg.com> wrote:
"Just a reminder, you still want a little signal
diode like a
1N4148 as I mentioned across 6 and 7. The other end gets connected to
a
resistor, and the other end of that resistor
gets connected to pin 8."
The protection resistor gets connected to the end of the pot opposite
pin 6. The protection resistor does not get connected to the diode.
To clarify my ambiguous wording
"Just a reminder, you still want a little signal
diode like a
1N4148 as I mentioned across 6 and 7. The other end gets connected to
a
resistor, and the other end of that resistor
gets connected to pin 8."
The protection resistor gets connected to the end of the pot opposite
pin 6. The protection resistor does not get connected to the diode.
G
George Herold
Guest
On Aug 31, 9:49 pm, Michael <mrdarr...@gmail.com> wrote:
The batteries in each were gone. But you can buy replacement gel cels
(I think I got them from Digi-key) for $10 each... two per vehicle..
Total cost about $30 per car. (Oh I hade to replace one of the foot
toggle switches that turns on the power.)
(Plus of course a bit of my time... but heck then I'm a hero to both
my wife and kids.)
George H.
Ohh don't do that, My wife got two at a garage sale for $10 each.On Aug 31, 6:16 pm, George Herold <ggher...@gmail.com> wrote:
On Aug 31, 3:57 pm, Michael <mrdarr...@gmail.com> wrote:
On Aug 31, 12:49 pm, George Herold <ggher...@gmail.com> wrote:
On Aug 31, 2:43 pm, Michael <mrdarr...@gmail.com> wrote:
I've got an electric car for the kids that has only an On-Off switch
for speed control. I was hoping to add a better speed controller than
that. I would need to PWM 12V, about 10-15A. I was hoping to use a
555 to generate the pulses to the mosfet gates.
I saw this:http://zeva.com.au/speedy/
I can appreciate the beefy freewheel diode and mosfets, but would I
really need a FET driver? At what point do I need a FET driver?
Would the output from a 555 suffice?
Thanks,
Michael
Is it one of the small 'power wheels'? (that is the fisher-price name
though there are other manufacturers.) With two small gel cel lead
acid batteries?
If so you can add a simple speed control by putting 'about' a 1/2 ohm
resistor is series with the battery. But I found that after a few
trips the kids want to drive it 'full on' all the time.
George H.
Nope, got it at a flea market. Originally runs on 6V, but that didn't
give a whole lot of power (step on the throttle, and nada). Put in a
higher A-h 6V battery, and works a little better, but still not much
power. Put in a 12V battery from a different project, and whoa, yee-
haw! A bit too much power. Wires got hot, too. So I'm planning on
re-doing the wiring, and adding a PWM control. Maybe a fan, but if I
do that, would that just fan the flames...?
I'm still annoyed that the original 6V battery charger that came with
it gave 8+ volts output across the battery terminals after charging
overnight. I shouldn't have trusted them, but hey... I gave them the
benefit of the doubt. Now I use a dedicated 6/12V adjustable Pb-acid
battery charger.
Right now it's just sitting in the room, no one riding it, because the
6V battery (even the bigger one) doesn't give enough juice. A pity..
Michael- Hide quoted text -
- Show quoted text -
Hmm, I'm not much of an expert, but I would think that you might end
up frying the motors if you push to much current through them.
They're probably designed to run with the series resistance of the
battery to limit the current. (What's the 6V battery voltage when the
it's putting out 10 or 15 amps?) But if you don't mind wasting the
power a resistor in series with your 12V battery may do the trick.
Unless you are just wanting to learn about PWM circuits and all.
George H.
Learning, yep. Otherwise I would just plunk down a few hundred bucks
and get a genuine Fischer-Price vehicle.
Thanks,
Michael- Hide quoted text -
- Show quoted text -
The batteries in each were gone. But you can buy replacement gel cels
(I think I got them from Digi-key) for $10 each... two per vehicle..
Total cost about $30 per car. (Oh I hade to replace one of the foot
toggle switches that turns on the power.)
(Plus of course a bit of my time... but heck then I'm a hero to both
my wife and kids.)
George H.