fun h bridge for winch control
in [Design]
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From: ehsjr on 9 Oct 2009 10:45 acannell(a)wwc.com wrote: > On Oct 7, 5:04 pm, Joerg <inva...(a)invalid.invalid> wrote: > >>acann...(a)wwc.com wrote: >> >>>On Oct 7, 4:26 pm, Joerg <inva...(a)invalid.invalid> wrote: >>> >>>>acann...(a)wwc.com wrote: >>>> >>>>>oh you guys are gonna like this one... >>>>>so i bought a winch for my jeep but it didnt come with a controller >>>>>box. >>>>>so i need a way to connect the 12V from the jeep battery to the winch >>>>>ON and OFF like....and reverse it...so I can reverse the winch >>>>>direction >>>>>thats it! >>>>>needs to be controlled with a rocker switch, or two switches, whatever >>>>>the maximum steady-state current of the winch is about 300A, so the >>>>>switching circuit needs to handle that >>>>>and of course the winch is an enormous DC motor >>>>>so...whats a fun way to do this? bank of mosfets? something else? >>>>>i know i can just by a big relay/contactor, but i want to make this >>>>>myself... >>>>>suggestions? >>>> >>>>I would use a huge contactor. If it absolutely has to be electronic >>>>you'll need an H-bridge driver with integrated charge pump, like this: >> >>>>http://www.freescale.com/files/analog/doc/data_sheet/MC33883.pdf >> >>>>Then probably 8 or 12 of those, plus some discrete parts: >> >>>>http://ixdev.ixys.com/DataSheet/DS99630A(IXTH-TQ280N055T).pdf >> >>>>As you can see this gets a tad expensive. Also, you need to have some >>>>safety shut-down feature to cut power when the MOSFETs weld themselves >>>>shut. Or in case of a contactor if the contacts weld together. After >>>>all, you don't want the winch to keep cranking and then pulling your >>>>Jeep up a tree :-) >> >>>>Remember, you do this on your own risk, 300 amps and so much power is >>>>dangerous. >> >>>>-- >>>>Regards, Joerg >> >>>>http://www.analogconsultants.com/ >> >>>>"gmail" domain blocked because of excessive spam. >>>>Use another domain or send PM. >> >>>the fun begins! >> >>>why did you pick out a fet with a relatively low Ids? some of those >>>ixys parts go up to 700A+. is a bank of fets better than a single fet? >> >>That depends on the size of your wallet, lottery winnings and such. The >>FETs I suggested are slightly above $4 a piece. Four of these would also >>suffice but it'll come to a grand total of 1100 bucks because they cost >>$275 each: >> >>http://www.microsemi.com/datasheets/APTM10UM01FAG-Rev1.pdf >> >>Or this one for the "bargain price" of $150 a pop, ouch: >> >>http://ixdev.ixys.com/DataSheet/L286.pdf >> >>And then you do some outdoors stuff, get into a rain storm, lightning >>... *PHUT* ... hundreds of bucks gone. >> >>I have paralleled FETs many, many times and the reason was always the >>same: $$$. However, you may need resistors in series with each gate, >>usually something around 10ohms. >> >>Personally I'd use the traditional big old contactor :-) >> >>-- >>Regards, Joerg >> >>http://www.analogconsultants.com/ >> >>"gmail" domain blocked because of excessive spam. >>Use another domain or send PM. > > > Oooooh.. > > I'm thinking the design problems are: > > Being able to turn on the fets fast enough so they dont dissipate any > energy in their linear region. (requires some kind of high current > driver, like the one you suggested) > Being able to handle whatever inductive spikes the motor might throw > our way. (not sure how to do this. (can the fet body diodes take care > of this?) > Handling the current > > Anything else? > Yup. A fire extinguisher. When Joerg says *PHUT* ... *LISTEN* Ed
From: Paul Hovnanian P.E. on 9 Oct 2009 22:45 George Herold wrote: > > On Oct 8, 7:57 pm, "Paul Hovnanian P.E." <p...(a)hovnanian.com> wrote: > > Joerg wrote: > > > > > acann...(a)wwc.com wrote: > > > > On Oct 8, 6:24 am, George Herold <ggher...(a)gmail.com> wrote: > > > >> On Oct 7, 7:00 pm, "acann...(a)wwc.com" <acann...(a)wwc.com> wrote: > > > > > >>> oh you guys are gonna like this one... > > > >>> so i bought a winch for my jeep but it didnt come with a controller > > > >>> box. > > > >>> so i need a way to connect the 12V from the jeep battery to the winch > > > >>> ON and OFF like....and reverse it...so I can reverse the winch > > > >>> direction > > > >>> thats it! > > > >>> needs to be controlled with a rocker switch, or two switches, whatever > > > >>> the maximum steady-state current of the winch is about 300A, so the > > > >>> switching circuit needs to handle that > > > >>> and of course the winch is an enormous DC motor > > > >>> so...whats a fun way to do this? bank of mosfets? something else? > > > >>> i know i can just by a big relay/contactor, but i want to make this > > > >>> myself... > > > >>> suggestions? > > > >> 300 amps sems like a lot! I thought the alternator only put out 60A > > > >> or so? I guess they put bigger alternators in trucks and such. I've > > > >> got a small winch on my truck and just use a big rocker switch. > > > >> What's wrong with a even bigger switch? It's simple. > > > > > >> George H. > > > > > > The battery and the alternator work together to supply the current to > > > > the winch.. My winch only draws 30A under no load. But under full load > > > > (8000lbs) draws 280A. > > > > > > How big of a rocker switch?? Jeez how often do you use it? Most hand > > > > operated switches would not be able to handle winch current. > > > > > Well, that depends :-) > > > > >http://www.electroswitch.com/electroswitchesandrelays/images/itapSwit... > > > > > You can get switches rated at 1000 amps continuous. > > > > Not suitable for the application. The winch control switch is connected > > to the relay box with a 10 foot (or longer) cable. This way the operator > > doesn't have to stan next to the winch when that 5/8 inch diam cable > > snaps under tension. > > > > -- > > Paul Hovnanian mailto:P...(a)Hovnanian.com > > ------------------------------------------------------------------ > > politics; n, from the Greek 'poly' meaning many and 'ticks', small > > annoying blood suckers.- Hide quoted text - > > > > - Show quoted text - > > Mind if I ask another 'stupid' question? > What gauge of cable do you use to run to the box? My Warn winch uses #2 stranded copper from the battery to the relays and then to the motor. The control switch appears to be made up of 3#16 SO cord. > I've got a left > over hunk of 12 gauge that runs to the rocker switch (60A max, maybe 5 > feet of cable). 12 gauge will be fine for the control circuit (the relay coils). Use stranded conductor suitable for flexible cord applications. > Ahhh the light begins to dawn. You have to mount the > switch on the motor. What are you going to do about water? The relays go on the motor (within a few inches of it). The control switch must have a long enough cord so as to allow the operator to take cover in the event the hardware snaps. Actually, my cable is long enough so I can run the control switch to the driver's seat (through an open window) so I can steer while pulling. Water isn't a big deal for the motor and relays. If its clean, it'll dry out. If its full of sediment, you'll have to tear the winch down and clean it. -- Paul Hovnanian mailto:Paul(a)Hovnanian.com ------------------------------------------------------------------ I like long walks, especially when they are taken by people who annoy me.
From: Paul Hovnanian P.E. on 10 Oct 2009 14:10 Rich Grise wrote: [snip] > > if it's series wound > (universal), you have to swap either the armature or the field, but > not both. That's how Warn does it. Picture an H bridge (made of relays) controlling the field. Battery (+) comes in the top of the bridge. At the bottom (where you'd expect (-), the bridge is connected to the motor armature. -- Paul Hovnanian paul(a)hovnanian.com ---------------------------------------------------------------------- Have gnu, will travel.
From: JosephKK on 13 Oct 2009 09:41 On Wed, 07 Oct 2009 17:55:26 -0700, Joerg <invalid(a)invalid.invalid> wrote: >acannell(a)wwc.com wrote: >> On Oct 7, 5:04 pm, Joerg <inva...(a)invalid.invalid> wrote: >>> acann...(a)wwc.com wrote: >>>> On Oct 7, 4:26 pm, Joerg <inva...(a)invalid.invalid> wrote: >>>>> acann...(a)wwc.com wrote: >>>>>> oh you guys are gonna like this one... >>>>>> so i bought a winch for my jeep but it didnt come with a controller >>>>>> box. >>>>>> so i need a way to connect the 12V from the jeep battery to the winch >>>>>> ON and OFF like....and reverse it...so I can reverse the winch >>>>>> direction >>>>>> thats it! >>>>>> needs to be controlled with a rocker switch, or two switches, whatever >>>>>> the maximum steady-state current of the winch is about 300A, so the >>>>>> switching circuit needs to handle that >>>>>> and of course the winch is an enormous DC motor >>>>>> so...whats a fun way to do this? bank of mosfets? something else? >>>>>> i know i can just by a big relay/contactor, but i want to make this >>>>>> myself... >>>>>> suggestions? >>>>> I would use a huge contactor. If it absolutely has to be electronic >>>>> you'll need an H-bridge driver with integrated charge pump, like this: >>>>> http://www.freescale.com/files/analog/doc/data_sheet/MC33883.pdf >>>>> Then probably 8 or 12 of those, plus some discrete parts: >>>>> http://ixdev.ixys.com/DataSheet/DS99630A(IXTH-TQ280N055T).pdf >>>>> As you can see this gets a tad expensive. Also, you need to have some >>>>> safety shut-down feature to cut power when the MOSFETs weld themselves >>>>> shut. Or in case of a contactor if the contacts weld together. After >>>>> all, you don't want the winch to keep cranking and then pulling your >>>>> Jeep up a tree :-) >>>>> Remember, you do this on your own risk, 300 amps and so much power is >>>>> dangerous. >>>>> -- >>>>> Regards, Joerg >>>>> http://www.analogconsultants.com/ >>>>> "gmail" domain blocked because of excessive spam. >>>>> Use another domain or send PM. >>>> the fun begins! >>>> why did you pick out a fet with a relatively low Ids? some of those >>>> ixys parts go up to 700A+. is a bank of fets better than a single fet? >>> That depends on the size of your wallet, lottery winnings and such. The >>> FETs I suggested are slightly above $4 a piece. Four of these would also >>> suffice but it'll come to a grand total of 1100 bucks because they cost >>> $275 each: >>> >>> http://www.microsemi.com/datasheets/APTM10UM01FAG-Rev1.pdf >>> >>> Or this one for the "bargain price" of $150 a pop, ouch: >>> >>> http://ixdev.ixys.com/DataSheet/L286.pdf >>> >>> And then you do some outdoors stuff, get into a rain storm, lightning >>> ... *PHUT* ... hundreds of bucks gone. >>> >>> I have paralleled FETs many, many times and the reason was always the >>> same: $$$. However, you may need resistors in series with each gate, >>> usually something around 10ohms. >>> >>> Personally I'd use the traditional big old contactor :-) >>> >>> -- >>> Regards, Joerg >>> >>> http://www.analogconsultants.com/ >>> >>> "gmail" domain blocked because of excessive spam. >>> Use another domain or send PM. >> >> Oooooh.. >> >> I'm thinking the design problems are: >> >> Being able to turn on the fets fast enough so they dont dissipate any >> energy in their linear region. (requires some kind of high current >> driver, like the one you suggested) >> Being able to handle whatever inductive spikes the motor might throw >> our way. (not sure how to do this. (can the fet body diodes take care >> of this?) >> Handling the current >> >> Anything else? >> > > >That's pretty much it I believe. The body diode ratings are in the >datasheets. They are usually very staunch, I use the body diodes in my >designs a lot. Just the same, i would put some snubbers in there. BTW get a HUGE battery. At 300 A, a 50 Ah battery lasts maybe 10 minutes.
From: PeterD on 13 Oct 2009 12:25
On Tue, 13 Oct 2009 06:54:13 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: > >Actually, the steel cable (or wire rope) will store quite a bit more >energy (much higher tension per unit cross section). The nylon strap >will smash windows and people pretty good, but wire rope will cut a >person in half or even split a car. I have seen the movies, pretty >gruesome. Even chains will store energy (despite common conceptions that they don't). I took out a windshield with a chain once, no fun. Was glad I was wearing sun glasses that day, chain didn't make it through the glass, but glass fragments made it to the back of the truck (a distance of almost 12 ft!) The safest is synthetic winch cable, as long as it doesn't have a metal hook on the end. We use very overrated hooks so that the cable will fail before the hook. Seems to be the best solution. Biggest issue with synthetic cable is taht you must baby it so it doesn't get damaged. |