electric motor/ variable speed control
Im attempting to build a baseball pitching machine myself. Most every electric single wheel pitching machine I see online has a 1/4 hp electric motor. I have a 1/4 hp electric motor but Id like to add a switch to vary the speed. Question #1 Im not exactly sure of the correct way to do it or if I need a certain type of motor. If anyone has any suggestions Id appreciate it. Question #2 This question may be better answered in another part of the forums. All of the pitching machine tires/wheels I see online come with a 4 hole lug design. Im assuming I need to buy or fabricate some type of simple 4 hole wheel hub to mount onto the shaft of the electric motor. What is the best way to go about this. It doesnt seem like it would be very hard to make something that would work but it seems like it would be very difficult to get it mounted perfectly straight on the shaft so that the wheel spins true and balanced. I would think that this part could be purchased somewhere but I cant seem to find it anywhere online. Suggestions please? thanks in advance. heres a link to a picture similar to what im trying to build if youre having a hard time with my description http://www.plans-that-work.net/info_...el_pitchin.htm Unfortunately it take quite a bit more than a switch to vary the speed of a motor. In fact, I suspect that the machine shown in your link is using a direct current (DC) motor and a variable voltage DC power supply to vary the speed. Changing the speed of your 1/4 horsepower AC motor would require a frequency changing circuit and that will not be cheap. You can probably find a DC permanent magnet motor in one of several surplus sales sites on the Internet. I have one that I think I paid about $35 dollars for a few years back. I think it was originally built for a treadmill. You would also need a variable output DC power supply with an amperage output sufficient for the motor. Again, surplus is your best bet. The wheel, tire and hub are the easy part. Several surplus sites and also machinery sites have trailer wheels and hubs. You may need an adapter machined locally that would adapt the motor shaft to the hub although I think it would be better to have an intervening shaft with heavy duty bearings rather than put the stress of the wheel. tire and hub on the motor bearings. wow maybe im in over my head. i thought it might be as simple as wiring this http://www.espenergy.com/variable_speed_switch1.htm into my incoming power sourc. thanks for the reply. Well, that might work, but I don't think you would be pleased with the results. I tried one of those to slow down the blower in my old furnace and it caused the motor to make a lot of noise and a whole lot more heat than normal. I think if I had left it in the circuit for long it would have probably burnt out the motor. Those speed controls are really for fans and mostly for far less than 1/4 horsepower. Let me step in here a min as well.,, Furd pretty much got on the spot related the DC motors and he is correct. To change the AC motor speed is more than a simple voltage change they have to change the frequicty as well to order to run at diffrent speed. Those item are genrally can be found but the cost it will varies a bit depending on where you get it from. Now the fan speed controller you gave us on the link that one will NOT work with most AC motors due few reasons. 1} the 1/4 hp will useally draw about 4 amp 2} the controller you have on the link they are limited to about 2 amp and it will either overheat or burn out pretty quick. Merci,Marc Here's a 3/4 hp motor for twenty bucks. http://www.surpluscenter.com/item.as...tname=electric You would need to build a DC power supply for it but that can also be made from surplus parts. I found this motor in less than five minutes by doing a Google search for surplus dc motors. I'm sure I could have found several more that would work and maybe would be better suited. A question that is part of this topic. How does one change the speed of a DC motor? I am putting a 12v car fan motor to turn a seed spreader but I might want to slow it down if it runs too fast. Do I just need to drop the voltage? Tolyn Ironhand.,, related to the DC motor to change speed yes they are very senstive with voltage so when you reduce the voltage the speed will drop pretty much liner with the voltage drop. The series and PM [ Perment Magent ] motors are most senstive with the voltage / speed relationship. Other type of DC motors are not really senstive with speed change unless you have specal controller for that type of DC motor. Tolyn.,, to change the speed on car fan motor type useally use the restor bank what they used for multi speed control [ it will look like a two or three little coils ] those item is pretty common found. something like this [ it will be pretty close but not the exact the same but it will work for your useage ] hope that help ya Merci,Marc Thanks man! Car fan motors draw quite a bit of amperage, so that resistor bank would have to be pretty beefy. Even then, the heat it dissipates might burn it up. Many of the newer auto fans are controlled by pulse-code-modulation (PCM) from the computer, which drives a solid state relay. The driver circuit pulses the relay to turn on off to vary the speed. The faster it turns on off, the faster the speed. The motor receives 12 volts each time the circuit is switched on by the relay. It's not a difficult circuit to emulate if you have electronics experience: A 555 timer (oscillator) circuit can pulse the relay, which in turn runs the fan. The parts are a heckuva lot cheaper because they don't have to handle the high amperage. You could vary the speed mechanically. There is a type of continuously variable speed transmission often used on motors that consist of a pulley whose two haves slide open and close on the shaft to vary it's diameter. Or just use stepped pulleys. I got 2 12v fan motors from the junk yard (for free too!) got them home and they both are good (I did test them with a meter in the yard but I want to make sure when I got home). If I did want to use a resister and I want them to run at about 1/2 speed what size/kind resister do I need? Do I need to drop the voltage to around 6 volts? French, where did you get that picture? Never mind, I see there are a bunch of the controls that Rick was talking about. Thanks! to revisit this topic, for my 1/4 hp AC electric motor, would this be an appropriate switch to wire into the incoming power cord to vary the speed? http://www.grizzly.com/products/Rout...l-20-Amp/G3555 Sorry, but the answer is no. That is an SCR (Silicon Controlled Rectifier) speed control for universal type motors. A universal motor is a high speed (like the pictured router) motor that has a wound rotor and brushes. Drill motors and hand grinders are also universal motors. these are quite common in the automation and controls industry. They use a line connected (120VAC), simple, cheap, variable speed controller. They are normally brushed. Your application is not particularly demanding; that is, for either exact speed control or variable load.
Related Posts:
Electric fence
Electric FenceI have an MSEE and have been working as an electrical engineer for 3 years, before that, I was in Telecom and Electronic engineering. I put in this electric fence and discovered a ba...
Ge ecm programmable motor
GE ECM Programmable MotorI have GE ECM programmable motor, from my furnace that has failed. The motor is: Model 5SME39HL0307 Serial Number 0129YS Hp 1/2 120 volt. I have checked and a component on...
Has anyone tried electric radiant to cure cold basement rec room
Has anyone tried electric radiant to cure cold basement rec room?I'm trying to determine the best way to go in heating my basement rec room, and I'm leaning towards NuHeat electric radiant and til...
Furnace motor problem
Furnace Motor Problem?Furnace hums, will not turn on. Motor will not spin the blower, but motor hums, tries to turn it, it starts to move a bit and then stops. Motor getting hot. I can turn blowe...
Electric andersen windows stuck open
Electric Andersen Windows Stuck Open ..I have a set of Andersen awning windows with electric openers .. and after a recent electical storm the controller ceased functioning. I believe it to be the...
