I should have taken a photo but did not think about it. OK, here is the story. I visited my sister-in-law today and she showed me a tree she had cut down using her electric chainsaw. I asked her if she had watched videos on felling trees and she assured me she had. When I saw the tree she did everything wrong. She made two cuts at an angle for the notch; about 45° apart, and then she had made a cut on the backside that left a round hing in the middle. She also put herself between the tree and a fence, no room to get out of the way. I read her the riot act, told her what she did wrong, told her that if the tree had kicked up it could have hit her and killed her. She wanted to argue with me that she cut the notched correctly but I pointed to the tree and said that the evidence was clear. I told her no more cutting trees until she had proper instructions. I explained how she should be on the side of the tree where she had an exit path to move away from the tree once it started to fall. She also did not have any protective gear. She could have easily gotten hurt, the way she cut the tree it could have went in any direction. She cut the tree high; she is short so she had to reach up to make her cuts. The good thing is that I can use the tall stump to show her how to make a proper notch and backcut or bring her here to show her. The good thing is she does not have many trees on her property so maybe this will not happen again.
Kim, why not turn her on to the BC faller videos? Another good source for techniques is the Husqvarna how to videos. Either one would teach her how to read her stump and understand what she was doing wrong. If she reads her own hinge it will get through better than you telling her she is wrong. When you do it for yourself you are far more likely to believe the results. A round hinge is definitely wrong no matter how you go about it. A pair of felling wedge cuts at 45º to each other may not be all that wrong if it aligned the tree to fall in the right direction neither cut was too long and she followed up with a back cut or plunge cut in the right direction, but a round hinge means she did not.
Pull the plug on her electric saw next time In all seriousness though, dropping trees is dangerous work. To many people get hurt attempting it when they don't follow safety rules and understand how to do it properly.
Electric saws have a ton more torque than a gas powered one. The Kevlar cant stop the chain from spinning fast enough to keep you safe. Read #11 on Gemplers FAQ page here: Chain Saw Safety Chaps FAQs
I suggest scaring her to the point she will not cut again. Tell her you can drop it for her etc. I high cut with a bad notch is a recipe for dead or serious injury.
It is really simple. A series wound electric motor gets more and more torque as the motor speed drops. The saw is designed to give decent torque at normal running speed so as the chaps try to stop the chain the motor puts out enough torque to overcome the fibers in the chaps. The only safe way to stop a chain driven by an electric motor is to get rid of the electricity.
This is an interesting subject; it has been awhile since I studied electrical motors and it was not in practical applications; it was all theory using calculus. Looking at the torque formula: T = PW 9.549 / n where T = torque (Nm) PW = power (watts) n = revolution per minute (rpm) So yes, if the rpm goes to zero; which is known as locked rotor; the current goes exponential; and using the formula torque goes infinite. However, real world the locked rotor torque does not go infinite. Also, some AC induction motors don't necessary increase torque as rpm deceases. However, I would still recommend wearing chaps with an electric chainsaw because it may help to decrease the severity of the damage caused by the chain.
In golf carts those other motors are sepex motors I assume there called that in all aplications. The weaken or increase the field current mapping to increase torque or speed. And that's about all I know, the rest is or my head. Series motors don't have field currents.
Well this is kind of wrong. They both have field windings and currents but in a series motor is the same current flows through field and amateur. Sepex motors are variable to increase or decrease the field to increase torque or speed, and the direction it turns.
Nope. Just whenever I think I am an expert on any subject, I get it handed to me and realize that no matter how long or how much you know about something, there is always more to learn!
