Starter Solenoid: Underrated But Necessary for Smooth Vehicle Starting

1. Working Principle

The automotive starter solenoid turns on the primary circuit. After the coil is energized, the electromagnetic suction force is generated, and the movable iron core gets to work. The transmission meshing mechanism moves the starter pinion forward and engages with the engine flywheel gear ring.

On the other hand, the switch contact is pushed to turn on. The DC motor is energized to run, thus driving the engine to work.

The moving core is flexible in the brass sleeve, and a one-way forked device connects the moving core lever. The core is usually kept in the initial position under the action of the return spring. When the engine starts, the starter drive gear has to move forward about 12-20 mm.

Therefore, a large magnetic potential is required to generate the necessary initial suction force when the solenoid starts to run. The air gap decreases after the suction. And the electromagnetic energy increases sharply. It greatly exceeds the force required to maintain the closed state.

There are other requirements. The size and weight of the component should be as small as possible. In addition, high currents for reliable on-off are necessary.

2. Symptoms & Troubleshooting

Turn on the ignition switch to the starting position. The solenoid fails to respond. The reasons may be short circuits in the attraction and holding coil, ablation of the contact plate, and insufficient contact thickness.

Troubleshooting   

Turn on the ignition switch, and you can hear a "click" sound from the starter solenoid under normal circumstances. The drive gear is engaged with the flywheel gear ring. If there is no sound, the solenoid is faulty.

Remove the solenoid switch and disassemble it for inspection. If the attraction coil connector or the holding coil connector is broken, solder it firmly. If you don't have a soldering iron, clean the wire end of the holding coil and press it into the end cap screw. Finally, tighten the end cap screws.

In addition, check whether the contact plate is seriously ablation. If so, polish it with sandpaper, or turn it over and continue to use. If the contact thickness is not enough or there is severe ablation, just replace it.

Turn on the ignition switch. You can hear the "click" sound. However, the starter doesn't work. There are many reasons: overlap, the short or broken circuit of armature winding or magnetic field winding. Starter armature shaft bending, too tight or too loose bearing can also cause the failures.

Troubleshooting   

For the armature winding, we need to use a multimeter to determine where short circuits and overlap are. This issue is usually resolved by replacing the parts.

The broken circuit is rare because the armature winding wire is thick. The internal is not easy to break. The issue is often caused by the wire head-off or wire thrown out.

In the many failures of the magnetic field winding, overlap and broken circuits are the most common. When the vehicle is running, the current is quite large. It is easy to burn the wire, and the engine loses power.

If desoldering or general fracture happens, it's OK to continue to use after welding. However, problems caused by scorching must be removed by replacing the parts. Short circuit rarely occurs, and replacing the component is the only solution.

Symptoms are the slow rotation of the starter, lack of power and hard engine starting. The causes may be too large gap between the front and rear copper sleeve, bent armature shaft, commutator overlap, bad brush or too small spring tension.

Troubleshooting

Too large gap between the front and rear copper sleeve causes the armature to swing radially, resulting in a short circuit. This affects the regular operation of the starter and increases the resistance to starter rotation, making it difficult to start.

Therefore, new graphite bronze bushings should be used. The fit clearance between the armature shaft and copper bushing should be 1 mm.

If the rear end cover gasket wears out or the front end cover is loose, the armature is not tight. In addition, check whether the brush is terrible or the brush spring tension is too small.

The holding and attracting coils of the starter solenoid should be replaced if they are broken or short-circuited.

Usually, the holding coil is enclosed in the iron case of the solenoid. It can be removed by picking off the rolled edge of the housing with a flat shovel. The outer attractor coil will not be disconnected but should be removed first. Remember the turn number of the coil when removing the wire so that a new coil can be copied.

The burned part can be repaired by overlay welding. Next, polish the surface with sandpaper. Ensure that each pair of contacts can be contacted with the contact plate at the same time. There should be no obvious height difference. The amount of stacking should not be too much.

3. Reasons for Choosing Delcoribo Starter Solenoids

Turn on the ignition switch, and current flows to the starting system. There must be crucial components to take charge of the starter circuit and activate the starter motor. Delcoribo produces good starter solenoids to perform this specific task. We pay attention to everything, from plunger, return spring to windings. The high-standard manufacture ensures perfect performance.

Working under constant circuit and high torque, components need fine raw material and robust construction to resist corrosion and abrasion. Our parts are available to resist rust, dust and high temperatures. The strict quality management leads to lasting durability and prevents frequent replacement.

Delcoribo starter solenoids are easy to install in engines. Car owners can even change by themselves. New products are guaranteed to meet requirements. Come and get what you want!