How To Rewind The Rotor Of The Makita 2450 And 2470 Rotary Hammer With Your Own Hands

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• Where to begin?
• How to find a short circuit in the rotor
• The procedure for disassembly, repair, assembly of the rotary hammer rotor
• Stage I
• Stage II
• Stage III
• How to wind a rotor with your own hands.
• Option I
• Option II
• The rotor shell booking process
• The impregnation process of the rotor coils
• The process of stripping the collector from excess impregnation
• Anchor balancing process

If you have determined that the rotor is out of order in your hammer drill, and you don’t have the funds for a new one, or you have a desire to resurrect the part with your own hands, then this instruction is for you.

The Makita puncher device is so simple that the repair of Makita 2450, 2470 does not cause any particular difficulties. The main thing is to stick to our advice.

By the way, almost every user with the initial skills of a locksmith can do the repair of a punch with his own hands.

Where to begin?

Since the device of the punch is simple, the repair of the makita punch should begin with its disassembly. Disassembling the punch is best done in the already proven order.

Punch disassembly algorithm:

1. Remove the back cover on the handle.
2. Remove the electric carbon brushes.
3. Disconnect the mechanical block housing and stator housing.
4. Disconnect the rotor from the mechanical block.
5. Remove the stator from the stator housing.

Remember, the stator housing is green, the mechanical block housing with the rotor is black.

Having disconnected the rotor from the mechanical block, we proceed to determine the nature of the malfunction. Rotor Makita HR2450 pos. 54; article 515668-4.

How to find a short circuit in the rotor

Since you make an independent repair of rotary hammers, you need an

electrical diagram of the Makita 2450, 2470 rotary hammer.

In the Makita 2470, 2450 perforators, AC collector motors are used.

Determining the integrity of a brushed motor begins with a general visual inspection. The faulty rotor, pos. 54, shows traces of a burnt winding, scratches on the collector, traces of burning on the collector lamellas. A short circuit can only be detected in a rotor that has no open circuit.

To determine a short circuit (SC), it is best to use a special device IK-32.

Video:

After making sure, using the indicated device or a homemade device, that the rotor has a short circuit between the turns, proceed to disassemble it.

Be sure to fix the winding direction before disassembling. This is very easy to do. Looking at the end of the rotor from the collector side, you will see the winding direction. There are two directions of winding: clockwise and counterclockwise. Record and write down, you will definitely need this data when winding yourself. The rotor of the Makita hammer drill has a clockwise winding direction, right.

The procedure for disassembly, repair, assembly of the rotary hammer rotor

Here is the sequence for repairing a short-circuited rotor:

1. Trimming the frontal part of the windings.
2. Removing the collector and frontal parts and measuring the diameter of the removed wire.
3. Removing and cleaning the insulation of the grooves by counting the number of turns along the cuts.
4. Selection of a new collector.
5. Installation of a new collector.
6. Manufacturing of blanks from insulating material.
7. Installing sleeves into grooves.
8. Anchor winding.
9. Pin wiring.
10. Heat shrinking process.
11. Shell booking.
12. Shell impregnation.
13. Collector impregnation
14. Milling grooves in collector lamellas
15. Balancing
16. Rotor cleaning and grinding.

Now let's look at everything in order.

Stage I

At the first stage, the collector must be removed from the anchor. The collector is removed after boring or sawing the winding frontal parts.

If you are making an independent repair of the hammer drill, then you can cut the frontal parts of the winding using a hacksaw for metal. Clamping the rotor in a vise through the aluminum spacers, cut the windings in a circle, as shown in the photo.

Stage II

To release the collector, the latter must be clamped with a gas wrench by the lamellas and turned together with the cut off frontal part of the winding, turning the key in different directions.

At the same time, clamp the rotor in a vice through soft metal gaskets.

Similarly, remove the second frontal part using the gas wrench.

Always check the strength of the rotor in the vise by constantly tightening the clamp.

Stage III

When you remove the collector and the sidewalls of the winding, proceed to the removal of wire residues and traces of insulation from the grooves. It is best to use a hammer and an aluminum or copper chisel for this. The insulation must be completely removed and the groove surface cleaned with sandpaper.

But before removing traces of the winding from the groove, try to count the number of turns laid in several grooves. Use a micrometer to measure the diameter of the wire you are using. Be sure to check how much the rotor slots are filled with wire. If the filling is small, a larger diameter wire can be used with a new winding.

By the way, you can clean the insulation by wrapping a piece of wood of the desired profile with sandpaper.

Select a new manifold of the correct diameter and design. The installation of the new collector is best done on a block of wood with the rotor shaft upright.

Putting the collector onto the rotor, press the collector into its old place with soft hammer blows through the copper adapter.

The turn came to the installation of insulation sleeves. For the manufacture of insulation sleeves, use electrocardboard, syntoflex, isoflex, varnished cloth. In short, what is easiest to acquire.

Now the most difficult and responsible part.

How to wind a rotor with your own hands

Rotor winding is a laborious and complex process and requires perseverance and patience.

There are two winding options:

• By hand without winding devices;
• With the use of the simplest devices.

Option I

According to the first option, it is necessary to take the rotor in the left hand, and the prepared wire of the required diameter and the required length with a small margin in the right hand and wind it, constantly controlling the number of turns. Rotation of the winding from itself clockwise.

The winding procedure is simple. Secure the beginning of the wire to the bearing, thread the lamellae into the groove and start winding in the rotor groove opposite the lamella groove.

Option II

To facilitate the winding process, a simple fixture can be assembled. It is advisable to assemble the device when winding more than one anchors.

Here is a video of a simple tool for winding brushed motor rotors.

But you need to start winding with data preparation.

The list of data should include:

1. Rotor length = 153 mm.
2. Collector length = 45 mm.
3. Rotor diameter = 31.5 mm.
4. Collector diameter = 21.5 mm.
5. Wire diameter.
6. Number of grooves = 12.
7. Coil pitch = 5.
8. Number of lamellas on a manifold = 24.
9. Rotor winding direction = right-hand.
10. Wire filling percentage = 89.

You can get the data on length, diameter, number of grooves and number of lamellas during rotor disassembly.

Measure the wire diameter with a micrometer when you remove the winding from the rotor slots.

All the data you need to collect during the disassembly of the rotor.

Rotor rewinding algorithm

The order of winding of any rotor depends on the number of slots in the rotor, the number of collector lamellas. You set the winding direction before disassembly and sketched it.

Select the reference lamella on the manifold. This will be the start of winding. Use nail polish to mark the starting lamella with a dot.

When disassembling the rotor, we found that the rotor has 12 slots, and the collector has 24 lamellas.

We also found that the winding direction is clockwise when viewed from the collector side.

Having installed insulating sleeves made of electric cardboard or its analogue in the grooves, having soldered the end of the winding wire to lamella No. 1, we begin winding.

The wire fits into groove 1 opposite, and returns through the sixth groove (1-6), and so on until the required number of turns with a step z = 5. The middle of the winding is soldered to lamella # 2 clockwise. The same number of turns is wound into the same section, and the end of the wire is soldered to lamella No. 3. One coil is wound.

The beginning of a new coil is made from lamella no. 3, the middle is soldered into lamella no. 4, winding into the same grooves (2-7), and the end on lamella no. 5. And so on until the last coil ends on lamella # 1. The cycle is closed.

Having soldered the ends of the windings to the collector lamellas, we proceed to armoring the rotor.

The rotor shell booking process

The rotor is armored to secure the windings, lamellas and to ensure the safety of the rotor and its parts when operating at high speeds.

Reservation is the technological process of securing the rotor coils using a mounting thread.

The impregnation process of the rotor coils

The rotor must be impregnated with an AC connection. This is done with LATR. But it is better to do this procedure using a transformer, to the winding of which an alternating voltage is supplied through the LATR.

Photo of impregnation with LATR

The problem is that when an alternating voltage is applied, the turns of the wound coils vibrate and heat up. And this contributes to better penetration of insulation inside the turns.

It is recommended to use epoxy adhesive as an insulating material.

The glue is diluted in a warm state according to the instructions. Epoxy glue is applied to the heated rotor winding using a wooden spatula.

Impregnation of the rotor of the Makita 2470 hammer drill at home

Allow the rotor to cool down after thoroughly soaking. During the cooling process, the impregnation will harden and become a solid monolith. All you have to do is remove its drips.

The process of stripping the collector from excess impregnation

No matter how carefully and accurately you apply the impregnation, its particles fall on the collector lamellas, flow into the grooves.

At the next stage, all grooves and lamellas must be thoroughly cleaned and polished.

The grooves can be cleaned with a piece of hacksaw blade, sharpened as for cutting plexiglass. And the lamellas can be cleaned with fine emery paper by clamping the rotor into the chuck of an electric drill.

First, the surface of the lamellas is cleaned, then the grooves of the collector are milled.

Let's move on to balancing the anchor.

Anchor balancing process

Balancing anchors is mandatory for high-speed tools. The Makita perforator is not such, but it is not superfluous to check the balance.

A properly balanced rotor will significantly increase the operating time of the bearings, reduce the vibration of the tool, and reduce the noise during operation. Balancing will be performed on knives, two guides set, horizontally using a level. The knives are set to a width that allows the assembled rotor to fit onto the shaft. The rotor must lie perfectly horizontal.

If the balance of the rotor is disturbed, then it will always occupy a position in which the excess weight will be below. To compensate, it is necessary to push the load from the opposite side under the coil spacer so that it does not go beyond the rotor diameter. And you can drill the excess metal from the side of the excess weight.

So, by rolling the rotor on knives, you can carefully balance it.

Everything! The rotor is ready for installation.