the electric screwdriver does not spin under load

Mistakes that are most often made when working with an electric screwdriver

The convenience of using a screwdriver is hard to overestimate. The tool belongs to the category of those irreplaceable things in the economy, which should always be on hand. Some in a friendly way even call it a “screwdriver. It’s really simple, safe and effective to use. And, it would seem, what can be difficult to work with a tool, little more complicated than a screwdriver. But it does not hurt to know some basic rules, because mistakes can lead to unplanned expenses, and sometimes considerable ones.

electric, screwdriver, does, spin

electric screwdriver battery recovery after a deep discharge

I work in the service center for repair of electric and gasoline power tools, power equipment. From time to time we get a cordless tool for repair. both client and pre-trade. with the reason for treatment: “The battery is not working/charging”. The prerequisites for this defect are usually:

HOW TO FIX CORDLESS SCREWDRIVER | Motor Not working | DIY | Disassemble

Today I would like to focus on the last variant. Deep discharging of the capacity occurs due to long storage of discharged battery, for example, in the cabinet in your home, or for example, in a cold room. the effect is manifested faster (I’m sure many are familiar with the situation when the battery of a smartphone in the cold is melting before your eyes). From our wholesale customers, it also happens that a brand new tool arrives with this problem. Most often, it turns out that they store tools all winter in unheated warehouses.

The root of the problem is that even if the battery is not used. It loses its charge, albeit slightly. The charge level in time drops below the minimum allowable value, and at a certain moment the protection module built into the charger/AKB control board or 18650 battery protection module refuses to accept the charge, believing that there is some problem with the battery (short circuit for example). The protection module is necessary for your safety. As a result. The battery does not pick up the charge, and empty it, respectively, also does not work. This is valid for the entire lithium-ion battery family, including.h smartphone batteries. The worst thing about deep discharge. the battery inevitably and irreversibly loses its capacity, so keep your cordless tool at least somewhat charged.

Battery/Battery deep discharge. the least of all possible evils and “cure” is very simple: bypass the control board of the battery / charger need to bypass the capacitors directly and charge them to a level where the board will consider the level of charge in the common circuit of batteries and start charging the battery. I suggest, moving on to practice)

Yesterday we received a pre-sale cordless electric screwdriver with 18V lithium-ion batteries, came from a wholesale customer’s store, with two non-working batteries. The problem was detected at the time of sale. Took it home for the weekend, specifically to write the post:

Both batteries are discharged, the display does not work, the charger does not pick up. Voltage. less than the minimum:

Necessary minimum (aka maximum). Multitester, a Phillips/TORX screwdriver and a dodgy cable. The tricky cable is made of any unnecessary ordinary USB cable and a 62 Ohm resistor (the resistor reduces the current and resistance for the most painless charging for the battery). The USB cable has 4 wires: the resistor hangs on the red VBUS 5V, the black GND does not touch. DATE and DATE- we don’t need it, we can remove it. The smart cable can be powered from any power adapter for a smartphone, a USB-connector for a PC, or even from a USB-connector on your TV. In general, any USB connector with 5V and from 400mA:

And here we are armed with everything we need. Hook the toothy crocodiles to the multimeter probes, set the mode “20V DC”:

An empty battery charges an empty 1.5 volt in less than a minute. If, before and after charging, the battery is not gaining a charge and shows 0. The battery has gone into protection. In our case all capacitors are gaining charge, i.e.к. electric screwdriver is new, it has not been used. From experience, on this particular model, it is sufficient to charge each capacitance to

1,5-1,6В. It happens differently, depending on the board, t.е. depending on the manufacturer and model. Answering the question “Why crocodile probes and not magnets?”. this way is better to control the process. The voltages of the capacitors should be the same after charging. Although the board equalizes the charge in the capacitors, from manufacturer to manufacturer it does so with varying success. Bottom line: if the capacitors have different charges. when the charge level reaches, for example, 4,2V on one capacitance and 3,6V on the other capacitance. the board stops charging when it reaches the maximum charge on one of the capacitors. As a result, we get the battery with 15-16V on board, it will suffice for a small pinch of screws, and then have to charge again. Charge with whatever you like (remember the skirt on the heat shrink. where the plus, where the skirt is not. minus):

Charged to 7-8V, check. The indication appears, the battery is charging:

Assemble the battery in the case, charge it, check it:

Everything works, everything is fine, everything is perfect. Do the same with the second battery. Each battery takes at most 15 minutes. After repairing of defect we give to the tool a day or two. If the battery voltage has not dropped. give the tool to the customer.

Faults of an electric screwdriver that cannot be repaired

an electric screwdriver can be thought of as an improved electric drill. It has three features that distinguish it from the classic drill:

The first two are basic, there are also mains screwdrivers. The main purpose of the tool: fast tightening screws. For any screw: a screw with metric thread or a screw, or a self-tapping screw, such characteristic, as tightening torque is defined. It is usually measured in Newtons per meter and can practically be thought of as a 10 cm long wrench, with a tightening torque of about 1 kg.

Screwdrivers are usually limited in their power output to 2-2.5 Nm. It is sufficient for tightening most screws in daily use in various applications: industry, construction, technical repairs, households. Torque limiter (ratchet) prevents screws from breaking.

Screwdrivers also solve the reverse problem: unscrewing screws and self-tapping screws, thanks to reverse rotation. Finally, battery power with quick battery changeover increases convenience and dramatically improves productivity. With battery power, there’s no need for personnel to carry cables or walk around constantly looking over their length and location.

The electric motor of an electric screwdriver does not turn

Faults of electric screwdriver motor do not differ much from similar problems of angle grinder, drill and other power tools. The first thing that can become the reason why the electric screwdriver does not work is the wear of the brushes of the electric motor, which can be easily replaced with new ones, which are not very expensive. A second cause is a failure of the armature winding or motor stator.

The electric motor of an electric screwdriver

The most common cause is an inter-twist short circuit due to a break in the insulation of the winding wires. Occurrence of a short circuit may be due to overheating of the motor from, so to speak, excessive work, that is necessary in time to let cool down the tool, give it a “rest”.

By the way, the overheating of an electric screwdriver can lead to a leakage of lubricant from the gearbox, which will cause failure of its main components, which were mentioned above.

Another problem can be observed in the electric motor armature: contamination or greasing of the collector, which transmits electricity to the motor from the brushes.

Brushes and electric screwdriver motor collector

The collector can be repaired at home yourself by washing and cleaning it with a fine emery cloth. But the windings of the stator and armature have to be restored in a specialized workshop or replace the motor completely for a new.

In conclusion, we would like to note that the electric screwdriver will work long and qualitatively if treat it with care, not showing “fanaticism” in its operation.

The main causes of faults

Screwdrivers can be mains and cordless. Their main faults are almost the same, and the differences are related to the type of power.

Electric screwdriver

If the device does not turn on, first check the condition of the socket, and then, if it is serviceable, inspect the plug. Often an electric screwdriver does not start because the contacts are burned. If both units are intact, you should inspect the cable, make sure it is intact, not kinked or overkinked. Also possible causes can be a faulty trigger, worn-out brushes or burned-out motor winding.

If the technique sparks, you need to look for a defect in the armature, electric brushes or motor collector.

Self-starting electric screwdriver reports that the power button is broken.

If the chuck has a backlash, the gearbox shaft is defective. If the chuck is jammed and the drill bit or bit cannot be removed, it means that the jaws are jammed. It is caused by a lack of lubrication or a broken chuck internals. If it still rotates, it is a gearbox fault.

If the ratchet is defective, inspect its locking paddles, spring and pins.

Cordless electric screwdriver

If the equipment does not turn on, check the charger and the condition of the battery. If it discharges quickly, its condition is diagnosed with a special tester.

Other faults of a cordless electric screwdriver are similar to the mains technique.

Electric screwdriver slowly rotates

Good time all day!And so friends, all probably now in their possession an indispensable tool-a cordless electric screwdriver or drill.And everyone must have faced with a very painful problem with these things as Ni-Cd batteries, they are known to suffer from a big disadvantage of memory effect, that is, they should be charged at the beginning of operation to memorize the peak charge current and also discharge them to a certain low discharge current threshold.And during operation Ni-Cd batteries should also be discharged so they will not remember a certain memory threshold, otherwise their capacity will be reduced, and hence the power is lost and the operating time with them is shortened, you have to recharge them constantly.And then one day, my brother pulled from work two screwdrivers, which were going to throw in the trash.One was with a set of batteries, the other without.The question of replacing the block for a new one came up, but it was not so simple.The manufacturer has changed the line of data screwdrivers and new blocks generally are not suitable for the old model, and from other companies, too, did not fit.In consultation with knowledgeable people, was given the advice: buy a new unit, open, and insert into the old or unsoldered each battery, measure, and buy a battery separately, solder, or another option, give a grandfather who sells Ni-Cd batteries remaking at radio markets.Visiting stores that sell construction electrical equipment and after finding out the price of redoing the unit from the grandfather, that’s what I was stifled by greed:).I began to seek alternative methods of restoration of the screwdriver.I went to the net, a lot of tips were the same which I got from knowledgeable people, but not so!Already desperate to see something new, I accidentally entered another request into the search engine and the Internet gave me completely different results.Opened one site, read, and here it is.Looking for! Well and now on the order, the fact that there are accumulators not suffering from the memory effect, have a small weight, compactness and power is not lost.This LiPo and LiFePo batteries, they are mainly used in aircraft modeling.Na ask silly question on the site decided to act, first we must determine the size of Accum (ie, measure the internal dimensions of the unit) their voltage (V) and power (in mAh), the same as your old (but keep in mind, the volts LiPo Accum-in not much lower than V Ni-Cd, but this will not affect the power of an electric screwdriver, ie 11.1V corresponds to 12 V and t.д.)Further our way lies in two sites that sell all the attachments to aircraft models Parkflyer and HobbyKing,the first is the Russian intermediary, both legal and language, because if you have problems with the mail or the sender, the site admins will solve the problem with the parcel and your order.Yes they take some % of the order, but you know who to ask.And the second site is purely a Chinese site, it has a lower price, but if you are strong in English or Chinese, then you here.I, of course, chose the Parkflyer.What did I order to retrofit the screwdriver: 4 batteries 7.4 v 1300 mAh two in each block, balance connectors 2S, discharge indicator 4S.Balance-Charger, adapters, power supply to the battery charger (not included) and a camera I ordered Ni-Mh batteries (I then ordered six more of the same and 12 pieces of 900 mAh, cool batteries!).I should have ordered two 14,8v 2200mAh LiPo batteries at once and not to mess around with the balancing wires.In general, I got a total of 1300mAh instead of the desired 2600mAh, and also 14.8v, but that’s enough!So calculate at once how you will connect them in series (as I ended up doing, losing power) or in parallel, increasing the power of an electric screwdriver.Well, of course the link to the site which helped me to restore the screwdriver, ask the creator of this thread on the site Kuryla and other guys, they will help with your questions.And now here are pics of how I redid my electric screwdriver.Yes, by the way, if you order the parcel, to wait from two weeks to 45 days, as our mail and customs, barely moving flippers.And order the parcel with tracking, trekr will help trace the movement of your parcel to the addressee.And don’t order packages during the holiday season, they will take a long time to arrive.Good luck to all who are interested in the topic!Write to me, if possible to answer your questions. Here is another link to the correct calculations of the charge / discharge of any accum-v

Measure the inner length, width, depth of the battery box

Here are my batteries, as I wrote above, missed the choice, but that is what is in the block 2 accumulators at 7.4v = 14.8v, and the power has remained the same 1300, and I wanted 2600mAh

I bought the connectors: 2 pairs of dongles for connecting balancing connectors in blocks and 1 mother for connecting to the balancing/charging unit.

Iron knocks machine (traffic jams). Why.

a block with soldered balance connectors

Wanna Repair/ Upgrade an Old Electric Screwdriver? Watch This First!

collect accumulators in block, connecting all loading and balancing wires.Seal the batteries with some material, in my case I used a foam material for pipes.I left two Ni-Cd batteries to support the contacts.

assemble the block, and do not forget to sign on each block with what charging current should charge.

next proceed to the disassembly of the electric screwdriver, because we need to make some changes to it, namely to insert the discharge indicator and its circuit in the operating position, that is, when you pull the trigger indicator shows a light and sound indication of the discharge of batteries.But you can find more details on the website.

I drilled a hole for the light indication behind the motor cover and glued the indicator light so that its LED was visible.Wires soldered accordingly. This is how it shines when the electric screwdriver is under load. Balanced battery charger, can also discharge LiPo, LiFePo, Ni-Cd, Ni-Mh, Pb-lead car batteries, can work from the car battery.Successfully discharged and discharged the Ni-Mh accumulators I bought, the maximum mAh of the power supply to the charger, sold separately.Runs quietly, no heat, tested! and Ni-Mh batteries, 10 pieces of 1.2v 2400mAh and 12 pieces of 1.2v 900mAh

Why does the chuck of an electric screwdriver rattles and twists?

Keep in mind the different interpretations of the concept of scrolling. When the clutch. torque regulator (ratchet) simply works, it is enough to select a different mode of its operation to fully screw in the screw.

If, however, the electric screwdriver cracks and scrolls when operating in previously unproblematic modes, it may indicate any of the tool’s faults:

  • Lack of sufficient grease of the appropriate type in the gearbox;
  • bent reduction shaft. this can be a factory or acquired defect;
  • The electric screwdriver has suffered physical damage or a full breakage of the satellite fixation pin, or the satellite itself;
  • wear of the working surfaces of plastic (less often metal) gears;
  • Bearing failure, fretting on the shaft.

Also, if the electric screwdriver starts to spin, the bit may not be securely seated in the chuck due to wear of the chuck jaws.

Electric screwdriver and its design features

Start the repair of the electric screwdriver with your own hands should be familiarized with its design. The main element of an electric screwdriver is the electric motor. Electric screwdrivers can be of the mains and battery type. The use of an electric screwdriver is resorted to less often, because of such a disadvantage as the need to connect the tool to a 220 V mains. Cordless type tools are more popular because they allow you to perform not only repair work at home, but also outside of it.

The main components of a cordless electric screwdriver are:

  • Housing. Usually all screwdrivers are made of durable plastic.
  • Start button. It is designed so that the amount of rotation of the chuck depends on the force of pressure on it.
  • Motor. Cordless tools use single-phase collector-type motors and DC motors. The motor is a rotor, a stator in the form of magnets, as well as a brush assembly.
  • Gearbox.
  • Force regulator.
  • Reversing switch.
  • Battery. This is generally detachable and often comes in duplicate with the product.
  • chuck. As a rule, quick-action chucks are used.

Some models are additionally equipped with LED illumination lights, as well as battery charging indicators. Returning to the problems with the electric screwdriver, it should be noted that any of the above elements can cause malfunction of the tool. What you need for repairs? The first thing to do is to find the cause of the breakage, and then make an appropriate decision about its elimination. The tool can be divided into two parts: electrical and mechanical. The first step is to find out whether the problem is mechanical or electrical. It is not very difficult to do this, so let’s consider the breakdowns in more detail.

Mechanical faults

Identify mechanical malfunctions of screwdrivers can be identified by such a sign as the audibility of the functioning of the electric motor. When you press the start button, you hear signs of the electric motor, but the tool chuck does not rotate, or when it rotates, you hear the characteristic sounds of failure.

The design of an electric screwdriver is quite simple, but a significant disadvantage is that all the elements are almost 2-3 times smaller than on an electric drill. Mechanical possible breakdowns of an electric screwdriver include the following malfunctions:

  • Chuck breakage. Although quick-action chucks are more versatile and easier to use, they have a major disadvantage: their low service life. It is impossible to repair a quick-clamp chuck, so if the tool refuses to hold a drill bit or bit, the chuck should be removed and replaced with a new one. This is one of the most common malfunctions of the tool, but it is not necessary to disassemble the electric screwdriver.
  • Gearbox failure. Screwdrivers have a planetary gearbox. Usually, in order to save money, manufacturers make gears from plastic or low quality metal. It not only affects the power output of the tool, but also the life of the tool. If the motor works when you press the “Start” button, but the chuck does not rotate, then the problem is in the planetary gearbox. To find out the cause of malfunction, you need to disassemble the tool and then determine the fault. Gearbox should be replaced if one pinion fails.
  • Bearing wear. The bearing is in the planetary gearbox, so it is replaced along with the gears.
  • Failure of the force regulator. In most screwdrivers, it is not only used to increase or decrease the pulling power of the tool, but also to improve safety. If the work tool jams during operation, the control turns instead of turning the tool. In this way, the hand is not dislocated, and the electric motor is protected from high loads from which it can burn out.

It should be noted that the small size of the mechanical part of the tool makes it somewhat difficult to repair the tool, so be sure to be careful when carrying out repairs.

Electrical faults

Unlike a drill, screwdrivers function primarily on batteries. This means that different electric motors are used in the construction of these tools. Determining the electrical part of an electric screwdriver malfunction is not difficult. If the battery is charged but when you press the “Start” button no sound is heard from the electric motor, there is an electrical problem. Let’s look at the main types of screwdriver faults by electrical part.

  • Battery malfunction. The first thing to look at is the battery. Typically, screwdrivers use low-quality nickel-cadmium batteries. They have the major disadvantage that it is only necessary to charge them when they are fully “dead. They must not be recharged, which will reduce their lifetime. If one day the electric screwdriver fails to function, do not rush to disassemble it, make sure that the battery is functional and gives a charge. This can be checked by connecting a second battery. The battery charge can also be checked with a tester, which should show the appropriate voltage value.
  • Charger malfunction. There is a special charger for charging the battery. If the battery is discharged even after you have charged it, you should check the integrity of the charger. For this purpose usually there are light indicators on the chargers. If they are not available, you should use a multimeter.
  • Faulty trigger. The starter button should be checked, because often the reason for its malfunctioning is oxidation of the contacts or dust. Take the tool apart and clean the contacts afterwards. Buttons usually on screwdrivers have a function to regulate the speed of the chuck, for which a transistor is installed. If the tool works, but the speed control function is missing, you need to replace the transistor.
  • If the reverse function does not work, you can fix the problem by cleaning the polarity reversal button contacts.
  • Motor failure. The electric motor is one of the most expensive components of an electric screwdriver. If all is checked and the problem is found to be in the electric motor, then the cause must be found. The most common problem is with the brushes, which over time are simply worn out. The brushes cannot be repaired, so they must be replaced. The armature should be replaced if a wire break is detected when testing the winding leads. No one will rewind such a small rotor, so it is easier to buy a new machine. The stator of a permanent electric motor is represented in the form of 2-3 magnetic plates, which do not fail.

Now you know the main signs and types of faults of an electric screwdriver. To repair it, you do not need to be an expert, but just have a tool and free time.

Breakage Causes of an Electric Screwdriver

When checking for faults, it is important to understand and see the earliest signs of trouble in the appliance.

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