Replacing Electric Trimmer Heads Foreman 8101
An electric braid or trimmer, like any electric tool, has a limited service life. With increasing intensity of operation for various reasons, the life of the device decreases.
It should be prepared that at any time during operation, the electric braid can break, but such situations can be avoided by regularly disassembling, inspecting and revising all important elements of the braid.
Failures of electric braids can be very diverse, it can be either a breakdown in the electrical part of the engine and wiring, or in the mechanical part.
In most cases, repairing a trimmer or scythe is not difficult and you can do it yourself if there is a minimal tool and basic concepts in the technique. Well, for readers of elektt.Blogspot.Com, I will reveal the main malfunctions and secrets for the quick and reliable repair of your electric braid, consider an example of repairing a Bosch and Gardener electric braid.
The design of most electric braids is not a complicated device, the main components, whether it is a trimmer or a braid, are an electric motor, a power cable, a button with a capacitor, a spool with fishing line that is attached to the motor shaft or more complex mechanical braids where the torque from the engine is transmitted to the spool through flexible shaft, but among electric braid options, this option is rare.
To detect malfunctions of the electrical part, as a rule, just one inspection is not enough, you need a multimeter or at least a tester with a continuity.
Such malfunctions are characterized, as a rule, by the complete inoperability of the engine, severe overheating or jerking.
The test begins with the power cable, if it is damaged, it is either repaired or replaced.
Express test involves checking the voltage of 220 volts on the motor contacts.
The voltage should appear when you press the button, if the voltage is present, you can safely say that the trimmer motor is faulty, it must be disconnected and carefully inspected.
Small contamination of the collector plates and brushes is normal, but it is still better to clean them with a soft cloth dampened with alcohol, if the worn brushes are clearly visible, it is better to replace them.
Using a multimeter in the resistance test mode (the smallest limit. Ohms), touch the brushes to the contacts of the brushes or to the graphite brushes themselves, the tester should show a resistance of not more than 100 Ohms.
If the resistance is infinite (unit on the multimeter) then try turning the motor shaft without removing the probes.
A faulty electric motor wakes up resistance of about 10. 40 Ohms, if the brushes do not ring, then there is no contact or the integrity of the stator windings is broken, a break or burnout is possible.
With a resistance of less than 5 ohms, there is an interspecific fault, most likely caused by severe engine overheating.
To identify the specific cause of the motor failure, when the motor brushes do not ring, you can resort to the following procedure.
Graphite brushes need to be pulled out, having previously stuck out brass inserts or having removed clamping springs.
The collector motors in these devices are so arranged that the stator and rotor windings are connected in series, and in expensive models of electric motors, a thermal relay (110 degrees) is also connected to this serial circuit, such a relay under normal conditions keeps the power contact closed.
A separate diagnostic method may be checking the resistance on the collector drum plates.
In order to identify the culprit of the malfunction, it is necessary to remove the insulation in the form of cambric from the fluoroplastic where the windings and the thermal relay are connected and ring each winding individually with a multimeter, as well as the thermal relay itself.
In electric braids, the most loaded mechanical elements can be called bearings and a trimeric coil (spool).
In most cases, the device stops mowing grass due to failure of its reel with fishing line
The fishing line is over. According to the instructions, you should wrap the fishing line on the reel.
Confused fishing line. If the reel is not damaged, then you need to cut or unwind the line and, if necessary, rewind the entire spool.
The fishing line stuck together. Due to the rather intense work and great overheating, the plastic threads of the fishing line can fuse with each other. It is necessary to rewind the reel with a new fishing line and inspect the damage to the bobbin itself.
The engine is running but the reel with fishing line does not rotate. Most likely there was a damage to the design of the reel with fishing line. The attachment points of the bottom of the coil can break off, you need to completely disassemble the bobbin and, if necessary, modify the mount or completely replace it. In most electric trimmers, the bobbin is simply pressed with its plastic housing onto the motor shaft and, if severely overheated, when the plastic melts, it can turn and fly off altogether.
Both devices did not show any signs of life; in the on state, the engines did not work.
The body of both devices consists of two halves, the screws are on one side, which is convenient to disassemble.
After all the screws are unscrewed, the upper case is separated from the lower one by gently pressing it with a flat screwdriver into the slot to open the interlocked plastic locks.
After disassembling, we proceed to the inspection of the insides and troubleshooting.
During the inspection, it was found on the engine trimmer bosch, on one of the brushes which is fixed by a clamping spring, the copper conductive wires flew off, which naturally was the reason for the lack of voltage on the brushes and the engine did not rotate.
The wire was restored to its place, and along the way, the collector sites were cleaned with a soft rag soaked in alcohol to a copper shine. The brushes were in good condition and did not need to be replaced.
It was also found that the switch does not create a reliable electrical contact, it was necessary to force the button to be clamped, it was decided to disassemble the button, its contacts were cleaned of soot and lubricated with a KONTAKT S-61 current-protective spray.
WITH electric braid GARDENER it was not so simple, she was lying quite a while for a broken state, and in the literal sense of the word "broken", its rod in the place of attachment of the engine casing was broken in half, apparently the operating conditions were so difficult.
Video: Replacing Electric Trimmer Heads Foreman 8101
With the help of perforated plates from the metal profile mounts, a new fastening of the engine casing to the electric brackets was not tricky. The integrity of the design has been restored, albeit not in an aesthetic, but in a reliable way, because the main thing in the electric braid is its functionality.
The engine shaft scrolled noticeably hard; during internal inspection, burned collector plates and worn brushes were found. The plates were cleaned with sandpaper to a shine, and the brushes were replaced with new ones.
In view of the long work without lubrication and subsequent storage of the device in an aggressive environment, the bearings are slightly stuck and the motor shaft does not naturally rotate with difficulty.
The engine bearings were flushed with WD-40 spray followed by lubrication. As a result, the engine began to rotate much better, but still the bearings were already "broken up" and when the engine was operating from the mains, the sound of its operation was not so smooth and monotonous.
Further inspection of the electrical part led to the button, it was completely broken from its mounts, although it was pressed, but the tester showed its malfunction. The button is not collapsible therefore it has been replaced with a new one. Fixings had to be restored with hot glue.
In addition to the broken rod, there was a crack on the plastic protection, apparently someone did not drop it weakly. Scythe could work with her, but it was decided, as far as possible, to restore the design of the protection.
It is natural to simply glue such an object loaded and subject to shock with glue would not be a reliable solution. Therefore, using the same perforated plates from the metal profile, two brackets were made that created "monolithic" connection of two parts of a cracked case.
The plates were connected to the body using aluminum rivets.
When the lawn-mow was assembled, it was found that the rod at the points of attachment of the handle is poorly fixed and rotates, therefore, the places of pressing the plastic protrusions of the handle body with the metal of the rod were additionally sealed with a strip of cloth tape. Now the design has no extra backlash.
The main most common malfunctions of the electric braid and trimmers
Does not mow grass
In the reel (spool) ended fishing line. In most spools, the grid feed is semi-automatic, with a light hit of a spring-loaded button on the ground, the fishing line is fed to the exit. If the fishing line is not fed, then you need to remove and disassemble the reel. Spool and, if necessary, wind a new fishing line.
The fishing line may be too long due to the fact that the blade that is designated for cutting the excess length of the fishing line has become dull or not at all.
The length of the fishing line should be slightly less than the diameter of the protection.
A large hum and vibration during engine operation may indicate that the bearings need lubrication or they have completely used up their life.
The case of the reel with fishing line (spool) may also crack, it and the place of its attachment must be inspected for cracks and damage.
Most electric motors in braids and trimmers are collector and do not have a speed regulator, with a decrease in the voltage in the network. Revolutions and power decrease.
The spool of fishing line may not be wound correctly.
Perhaps the speed is hampered by the presence of a stuck twig or a rope wound around the shaft, you should inspect the structure. In a serviceable braid, the shaft should easily and without any effort rotate even after it has been dispersed with a finger.
Electric braid does not work
Does the engine spin? We look at the availability of power on the electric plug, if everything is in order, then the device needs to be disassembled.
If no obvious damage is noticeable, then begin the sequential ringing of the electrical circuits of the device.
With the help of a multimeter (tester), the power cord is called first, the fuse, if any, and the button.
If the button does not ring in the on state, then it should be replaced, or if it is collapsible, open and clean the burned contacts.
The cord may be broken, in which case the engine may start intermittently.
A malfunction of the engine can be the fact that when the button is turned on, there is a voltage of 220 volts on the contacts of the motor but it does not rotate.
Some electric motors are equipped with a thermal fuse that is built into the engine casing and has tripped due to overheating or simply failed. A working thermal fuse when the engine cools down should restore its operation.
We all have to engage in the refinement of personal plots of land – in the summertime and of course, to give a beautiful view of the plot:
- In the country;
- In a private house,
– Do not do without a trimmer. The causes of breakdowns of electric trimmers is a strong vibration \ during operation \, which affects the various electrical connections of this appliance.
Before us is a photograph with the technical data of the electric trimmer. Trimmer repair will be accompanied by personal photographs with a detailed description of the repair.
Electric trimmer circuit
The electrical circuit of the trimmer with fishing line, simple, consisting of:
- Potentiometer; motor control speed;
And directly to the electric motor itself.
The cause of the malfunction at the beginning during the visual inspection was incomprehensible, the trimmer had to be disassembled completely to determine the true cause of the failure.
Dismantling the trimmer
Proceed to disassemble the electric trimmer:
At the beginning, we disconnect the two connected halves of the trimmer, the control handle from the contact connection with the electric motor itself.
Two photographs \ photo No. 2, photo No. 3 \ shows the sequence of separation of the electric motor from the control handle.
Next, we need to check, perform diagnostics – control knobs \ photo No. 4 \. We disassemble this part and carry out diagnostics for individual electrical connections \ photo No. 5 \.
Check with an indicator screwdriver
To check the electrical connections we need a simple tool – an indicator screwdriver.
Photo 6 shows a detachable contact connection from the control handle. To check the electrical circuit of the connections from the plug contacts \ photo No. 7 \ to the detachable contacts \ photo No. 6 \, for this, you can short-circuit the plug with the fingers of your left hand and, alternately, connect the indicator screwdriver tip to the detachable contacts.
With integrity, the absence of any gap \ photo No. 9 \ in the electrical connections, the indicator light of the indicator screwdriver will be lit, that is, the electrical circuit is closed on the LED lamp of the indicator screwdriver.
Performing this diagnosis, it is also necessary to close the contact of the potentiometer \ push contact \ as shown in picture No. 8.
We checked one half of the electric trimmer \ control stick \ – the handle of the manual trimmer is in good condition and then we need to check the second half of the trimmer, consisting of an electric motor and a capacitor.
Diagnostics with a multimeter
We will need for such a check – a digital multimeter. You can also use a pointer multimeter or a device such as an ohmmeter – there is no difference at all.
We set the digital multimeter in the measuring range of the lowest resistance, connect the probes of the device to the socket of the detachable connection \ output contacts of the electric motor \. The device in this example \ photo No. 10 \ here shows a unity, – the display of the device indicates a break in the electric circuit of the electric motor.
We need to look further at what could be the cause of the malfunction, and of course we will need to disassemble the two connected parts of the housing where the motor circuit is located directly.
Checking the collector motor
First, check the collector motor. We connect the probes of the device to the contacts of the graphite brushes \ photo No. 11 \, the display of the device shows the resistance as shown in the photo – 29 Ohms. The reading indicates the integrity of the stator windings of the collector motor.
We look further at what could be the cause of the malfunction. We conduct diagnostics of wires, output contacts of a detachable connection from an electric motor with contacts of graphite brushes.
We wrap two output contacts from the electric motor with the fingers of one hand and touch the contacts of graphite brushes with the tip of an indicator screwdriver \ photo No. 12, photo No. 13 \.
And when checking the data of the electrical sections, the cause of the trimmer malfunction is detected.
In the contact connection of the wire \ photo No. 13 \ with a graphite brush, the contact is broken. The elimination of such a malfunction does not present any difficulty. To do this, it is necessary to etch the contact connection with the wire and the contact connection with the graphite brush with soldering acid \ photo No. 14 \. Next, apply a small layer of tin with a soldering iron \ photo No. 15 \ and solder the wire with the contact of the graphite brush \ photo No. 16 \.
So, the cause of the malfunction of the "electric trimmer with fishing line" is installed and eliminated. As you have seen for yourself, such causes may be minor breakdowns that can be determined without any difficulty.
It remains for you all friends to wish a successful repair in troubleshooting various electrical equipment.