Electric Lawn Mower Wiring Diagram – Black & Decker makes a significant range of wired electric motors (eg LM175, MM275, MM575). My parents and I own 3 of these mowers and love them. They have provided great service over the years, but like all products, they have their downsides. This page describes the repair of these electric cutters.
In general, corded electric lawn mowers are fairly simple devices. Aside from the wheels, the Black & Decker model has only two moving parts: an electric motor and an electric switch assembly. The electrical system consists of only three parts: the motor, the switch assembly and the standard bridge rectifier.
Electric Lawn Mower Wiring Diagram
The motor used in this mower is exactly what you would find on a treadmill. Of course, these motors were probably originally developed for treadmills. The motor is a permanent magnet DC motor designed to operate on 120V DC.
Troubleshoot And Resolve Greenworks Lawn Mower Problems
The mower’s power input is 120 Volt AC “Standard Household Power”. The AC-DC conversion is done using a bridge rectifier and requires only 4 diodes in the box. The rectifiers used on most of these mowers come in MB or GBPC packages with four “faston” connectors for wiring and a central screw hole for mounting the heatsink. The maximum output of the rectifier is approximately 170V DC at 120V AC input.
The switch assembly consists of a power input port and a push button. The switch is dual axial. Single Throw (DPST) is a toggle action switch. This means that the switch controls two separate circuits when circuit #1 is “on” and circuit #2 is “off”. Furthermore, the switch has an intermediate moving region where the two circuits are “closed” to prevent shorting through the bridge rectifier.
#1 controlled by the switch connects the AC “hot” wire to the bridge rectifier. Circuit #2 controlled by the switch is the connection of the motor’s + and – terminals. OK, if circuit #2 is “open”, there is a short circuit at the motor terminals. This electrical deceleration of the motor is called “plug-break”. This is done because it is desirable for safety reasons to stop the motor as soon as possible after releasing the handle. However, I doubt the method of shorting the motor to implement plug braking would work.
The wiring diagram above applies to most Black & Decker cord cutters. The four lines through the dotted lines represent the wiring harnesses from the switch assembly to the mower deck. The light blue wires on the mower are actually white.
Cordless Electric Lawn Mower Grass Trimmer Portable Telescopic Lawn Grass Trimmer Mowing Machine Household Garden Tools|
Based on my family’s experience with three electric cutters, these models are prone to two types of errors: installation errors or bridge cutter errors.
Switch assemblies can be problematic in two ways. First, the switch can go bad if the contacts melt or fail. This is a function of lifetime and is somewhat expected given the high current flowing through what appears to be an intermediate switch. The second is a loose or melting wire between the input cord socket and/or the socket and the switch. Incorrect connections (eg cheap extension cords) can lead to corrosion of plug prongs and the like. Again, the high flow of the mower exacerbates these problems.
Bridge rectifier failure may occur due to excessive arcing or flashover of the motor commutator during power up. It doesn’t have a very large heatsink and is next to the motor (which can get very hot while running), so heat is most likely destroying the motor. When trying to cut very thick and/or wet grass, the motor and bridge cutter often heat up.
The mower’s bridge rectifier is very easy to replace. It is mounted adjacent to the motor at the top center of the cutter (see photo below). A rectifier has four connections, only two of which are normally labeled (+ and ~). In the wiring diagram above, there are two AC connections and two ~ and DC connections, marked + and – respectively.
Washing Machine Motor Wiring Diagram
Replacing the rectifier allows the two AC wires to be connected to one of the AC (~) terminals. However, the DC wires on the + and – terminals must be connected in the correct polarity. Otherwise, the motor will rotate backwards and the mowing blade will not cut in reverse. 😉
The original bridge rectifier (Black & Decker P/N 72256-03) is 400 volts. Rated for 15 amps. Parts from this factory sell for over $10. It’s fun because it’s a common part available at almost every electronics supplier.
Suitable substitutes include almost any bridge plan of the same grade or higher. For example, Diodes Inc. P/N GBPC2504 and MB254 are 400 volts. A 25 Amp rectifier is a decent replacement for less than $4. These are available from Digikey and other vendors. In general, mounting a rectifier with a higher current rating or increasing the size of the mounting plate will increase component life due to heat dissipation. Black & Decker manufactures a line of suitable wired electric actuators (e.g. models LM175, MM275, MM575). . My parents and I own 3 of these mowers and love them. They have provided great service over the years, but like all products, they have their downsides. This page explains how to retrofit a homemade switch assembly for this mower.
This page is intended for a specific individual and is not for public use. Therefore, it provides only educational value. This project is considered unsafe for several reasons…
Milwaukee M18 Fuel 21 In. Self Propelled Dual Battery Cordless Lawn Mower Kit
The safety of the mower will be reduced in at least two ways by making the following modifications: First, there will be no “dead-man” style buttons. This means that once turned on, the mower will run until it turns off (the default action is off when you take your hands off the handle). Second, the “plug braking” feature is deprecated. That is, after the machine is turned off, it takes about 7 seconds for the motor and mower to stop (small rooms stop in 1 second). The mower still cuts the grass. Do it at your own risk. You have been warned.
Read the main Electric Lawn Mower Wiring page first. Provides important background information you should know before reading this page.
If your lawn mower’s power switch does not work reliably; You can purchase a replacement switch (e.g. Black & Decker P/N 681064-01) and return it to factory working condition. Alternatively, the default switch/plug assembly can be replaced with a homemade switch assembly. This page explains how to make homemade buttons.
The mower’s basic switch assembly can be replaced with standard parts available at most hardware stores. This fix introduces some real safety issues. The electrical reliability of harvesters should be significantly improved.
Briggs & Stratton Power Products_del_26072017021729 8649 0
The image above shows the modifications to the original wiring. The light blue wire represents the white wire and the red and white wires on the motor should be covered or taped off (do not connect them together!).
Alternative action, double pole switches are hard to find. Therefore, replace the stock buttons with standard buttons (such as those found on the walls of buildings). Unfortunately, this means that “plug braking” of the motor is not possible with standard action switches.
Replacement switches can be single pole or double pole switches. The advantage of using a double pole switch is that the “hot” and “neutral” AC lines are disconnected when the switch is in the “off” position. It’s safer than a (cheap) single pole switch that only cuts one of the lines, as it guarantees that no voltage will flow to the motor regardless of the polarity of the AC wiring in your home.
When you buy a button, you’re looking for a “commercial grade” switch rated for 20A at 120/277V AC with a minimum rating of 15A. These are quality switches that can withstand the inductive “kick” that occurs when turning off the mower’s large electric motor. Don’t even think about using the cheap $0.49 “residential” level button.
Exmark Turf Tracer Hp S/n 600,000 669,999 Wiring Diagram
Harvesting using buttons, zippers, bolts, etc. requires handlebars to be installed in fireproof electrical boxes. Better to use a metal electrical box than a cheap plastic one. more durable. Metal “convenience” boxes are not waterproof, but are inexpensive. It is a good choice because it has no sharp edges and is relatively small in size. Also, never mow your lawn in the rain.
However, if a metal box is used, it must be electrically grounded to the home’s grounding system using a three-prong cable. If your home does not have a working soil management system,
Snapper lawn mower wiring diagram, lawn mower ignition wiring diagram, riding lawn mower wiring diagram, lawn mower wiring diagram, lawn mower coil wiring diagram, lawn mower starter wiring diagram, wiring diagram husqvarna lawn mower, lawn mower solenoid wiring diagram, murray lawn mower wiring diagram, toro lawn mower wiring diagram, craftsman lawn mower wiring diagram, lawn mower switch wiring diagram