Go to last comment about ' small electric motors?' Thank you for sharing... Thanks for your insight... Hi Kerry!! Thanks for coming by!! I think the greatest benefit... Excellent article, and such am important topic. I was happy to see you mention... Thank you ALL so much...
About 'small electric motors'-Electric Motor Winding Testing?
My Black & Decker CMM1200 Cordless Electric Mower was slowing down while mowing the yard and I did not know why. My initial thought was that the motor was not getting enough power. So I ordered a large dial, analog, 50 amp ammeter from Ebay.com. The ammeter came in and it was a used military surplus product so I felt a little nostalgia right away. I was going to reuse a piece of instrumentation that would have otherwise been thrown away. Of course, mowing with the installed ammeter is real fun because you can see the dial sweep back and forth as you go through thick grass! Why Should I Install An Ammeter On My Electric Mower? When you drive a car, you keep track of your fuel consumption by monitoring the miles per gallon (MPG). With electric motors, the standard measure of power consumption is with an ammeter. The ammeter monitors the amount of current flowing through the wires in your electrical circuit. Before you begin this project take extreme caution with all the wires. I recommend disconnecting one of the batteries so that you will not run a risk of turning on the electric mower. Contrary to popular belief, a healthy person without any heart conditions or electric implants cannot be harmed by 24 VDC. My concern is the mower accidentally turning on while you are moving the wires around inside. Remove The Black Plastic Top Cover Use a long, flat head screw driver with a narrow tip to remove the four bolts holding down the top black plastic top cover of the CMM1200 mower. The screws are going to be a little hard to remove because the bolt is designed for use with a special tool. Since none of us have that tool, you have to make do with a long, small tipped, flat head screwdriver. Once you have the four bolts removed, put them in a spare coffee cup so that you will not lose them. Cut The Black Lead Going Into The 24 Volt DC Electric Motor For many of you, this will be your first time interacting with a 24VDC, high torque, electric motor. The frame of the motor is over six inches tall and solid steel. The armature is enveloped with heavy gauge, solid copper, baked enamel wire for an imposing and powerful look. As a result, pulling 50 amps of power with this metal behemoth should be no surprise. The black lead going into the electric motor is called the negative pole. The only important rule with measuring current is to find the direction of the flow of power, not the polarity, which is why I can install the ammeter on the negative lead. Prepare both newly cut leads by removing 1 inch of insulation. You should exercise extreme care while doing this because you do not want to cut any of the stranded copper. Every piece of copper that you remove, while cutting the insulation off the wire, will further reduce the power available to the high amperage, electric motor. Heavy Gauge Wire Is Critical To Accurately Monitoring Current And Running The Mower Let's not forget that we have just cut the negative power feed for the cordless electric mower! If you wish to keep your lawn machine operating at peak efficiency then you have to use at least 8 AWG, stranded core wire for the leads running to and from the new ammeter. Placement Of The 50 Amp Ammeter On The Black Plastic Top Cover A gap of 3" exists between the batteries and the bottom of the cover so you will have more than enough room to sink the ammeter with its attached wiring. Pick a location on the cover so that you will have one inch or margin between the back of the cover and the bottom of the ammeter face. Now, draw out the hole that you will have to cut to sink the ammeter into the top of the cover. Use a Dremel tool or similar cutting device to cut a hole in the black plastic cover. Once complete, drill holes to accommodate the anchoring bolts and attach the needed bolts. Make sure the dial faces the handle of the lawn mower so that you can watch it while mowing. Finally, I used some black silicone sealant to create an air tight seal for the guage itself. I did not want any dust to get inside and ruin the delicate mechanical parts inside. Finishing All The Wiring And Testing Before Sealing The Top Cover Get your soldering iron out and connect 3ft of 8 AWG cabling to each of the cut leads from the motor. Now use some ring connectors to create a smooth, soldered, oxidation free, high amperage terminal for the end of both of the wires. You will now simple bolt these to the back of the ammeter. Before you put the black plastic cover back into position, turn on the cordless electric lawn mower first to ensure that the wiring is terminated in the correct position. You will know it is working if the needle on the ammeter hovers around 8 - 15 amps when resting on a sidewalk or similar concrete surface. If the needle jumps below 0 amps when you turn on the mower then you should switch the two leads on the back of the ammeter. Once you are sure it works, pull those screws out of the coffee cup and carefully place the cover back into position. I pushed the ammeter wiring to the left side of the battery bank since this area has no existing wires. Results As you can see from the photos provided with this article, the ammeter looks like it came with the Black & Decker CMM1200 cordless electric lawn mower. As soon as you turn it on, the gauge sweeps over to 50 amps and then swings back to 12 amps of consumption. I got sustained 40 to 45 amp readings while I pushed the mower through thick grass in the yard. After mowing the yard once with the ammeter installed, I quickly realized that I was pulling more than 50 amps of power once the batteries started running down. The control handle of the mower gave out a month ago and I can now see why this happened. Reduced voltage from the batteries lead to increased amperage pull from the motor which drives the switch circuitry far beyond what the factory electronics can deliver. The increased amperage drain also heated up the electronics in the control handle of the mower which degraded its ability to perform reliably the next time I mowed my lawn. Summary; Conclusions Drawn From Three Years Of Using The CMM1200 So far my most frustrating problem with the cordless mower is that I was not able to get my batteries charged with enough power because of the failing circuitry in the handle. As the switches in the handle lost their ability to make solid contact, the batteries no longer got a solid charge and the motor itself could not get enough power to cut grass. Ever since I replaced the jumble of wires with a single 40 amp, double pole, switch the mower has been able chew through the grass in my yard with ease. All thanks to what I learned from installing this ammeter. I never knew that I was pulling 50 amps of 24VDC power with this cordless electric lawn mower while working in the yard. All of my work shows that we still have a long way to go before gasoline engines can be cleanly replaced with electric motors. Still today, we do have options and I intend on getting the most out of these green machines, one step at a time. If you enjoyed reading this article, consider reading my series on solar power and renewable energy options: The Westinghouse Solar Light is Just $3 but Lasts for Years in Your Yard How Does a MPPT Solar Controller Work? Solar Power Project Part 3 How to Install a 50 Watt Solar Panel - Solar Power Project Part 2 How to Generate Your Own Electricity with Cheap Solar Panels - Part 1 |
Image of small electric motors
small electric motors Image 1
small electric motors Image 2
small electric motors Image 3
small electric motors Image 4
small electric motors Image 5
Related blog with small electric motors
Related Video with small electric motors
small electric motors Video 1
small electric motors Video 2
small electric motors Video 3