In the past two days, three electromagnetic locks have been processed in a row. The three locks look at the same shape. The circuit board can be divided into three grades, A Grade S4A magnetic lock , B, and C at a glance. No result, C-level this often kills the access control host .

Standard qualified magnetic locks (Like S4A brand) generally provide two input voltages of 12V and 24V (the difference between single coil and double coil), which are selected and switched by jumpers. There are several ways to judge the pros and cons of a magnetic lock:

(1)   Look at the circuit board

(2)   Measuring resistance

(3)   Measure the current value after power-on

(4)   Insulation value

(5)   The verticality of the cut steel sheet

(6)   Glue inspection

(7)   The distance of the cut steel sheet

(8)   No residual magnetism

(9)   4007 diode

(10) Process treatment of lock body shell

(11) High and low pressure

(12) Acidity test

(13) Finish

(14) Lock body electroplating

(15) Output line

1. Look at the circuit board

The inferior magnetic lock can be judged from the circuit board. The inferior magnetic lock circuit board has rough printing and very simple layout. It does not use varistors (that is, surge devices, generally there are two), and there is only one set of voltage input.

2. Measuring resistance

First unplug the 12V and 24V switching jumpers of the magnetic lock (note: no power is required), there are generally 4 binding posts (at the jumper), measure the red and black lines, and the resistance is about 50 ohms. good.

3. Measure the current value after power-on

After the magnetic lock is connected to 12V voltage, the current value is measured, and the one that matches the marked value is better. 280KG (600 lbs) magnetic lock is generally better at 400-450 mA. If it is less than 450 mA, it is not enough to pull; if the voltage is 24V, the marked or actual value should be 200 mA.

4. Insulation value

The insulation value of the lock body of a standard qualified magnetic lock should be infinite, and the specific value should be more than 50 megohms; the specific test position is the cut steel sheet and the lock body output line (any one).

5. The verticality of the cut steel sheet

In principle, the cut steel piece should be touched or stained with hands as little as possible. The perpendicularity and parallelism of the qualified magnetic lock cut steel piece should be as standard as possible. The quality of the electroplating of the cut steel sheet depends on whether there are oxidation marks on the cut steel sheet.

6. Glue inspection

The colloid of the magnetic lock should not have bubbles(Reference S4A Magnetic Lock), it should be flat and neat, without cracks, and the angle should be square.

7. The distance of the cut steel sheet

The main concern is that the thickness of the cut steel should be 0.35mm. At present, most of the cut steel on the market use 0.5mm cut steel; the tighter the arrangement of the cut steel on the lock body, the better. There should be no glue leakage during the arrangement.

8. No residual magnetism

Generally, the cleats of magnetic locks are made of pure iron, but most of the cleats are 99% pure iron, so they must have the function of removing residual magnetism. They are equipped with protruding rubber pads, which play a buffer role and have anti-residual magnetism devices. The lock will reduce the pulling force of about 35 kg; if the product of 99.9% pure iron is used, the generation of residual magnetism can be basically eliminated without the anti-residual magnetism device, and the pulling force is sufficient.

9. 4007 diode

Especially for locks that do not have indicator lights and signal output, this diode crystal is generally added to the positive and negative poles of the power supply of the lock. This treatment obviously shows that the material of the lock is not good enough, and some protection work is done here to prevent the positive and negative Extremely wrong connection or impact on the access control machine, etc.

10. Process treatment of lock body shell

The lock body shell is generally made of oxidation wire drawing or oxidation sandblasting, especially oxidation sandblasting, fine sand is preferred.

The wire drawing is neat, the money is sprayed evenly, and the cutting surface of the steel body of the shell is flat.

11. High and low pressure

Under low pressure, the lock can still work, but the pulling force is reduced; under high pressure, the lock body will become hot, and you should pay attention to the temperature rise at this time. If the temperature rise exceeds 20 degrees, it is an inferior product. Generally, the temperature rise data can be obtained within an hour. 

12. Acidity test

Use weak acid to coat the lock body cutting steel sheet, the good lock body will oxidize after 45 minutes, and the poor lock body will oxidize after 15 minutes. In addition, the lock body can be soaked in water, and the one that turns black within 24 hours is an inferior product.

13. Finish

Drop a small drop of water on the steel section of the lock body to observe whether it flows smoothly and whether it is muddy or watery. The smoother one has the best finish.

14. Lock body electroplating

Pay attention to the electroplating quality of the corners of the lock body. Wrinkles and darkening are not enough for the electroplating of the lock body.

15. Output line

The two-core one is an electric lock with no signal output, and the five-core one is with door position detection output.

At present, the suction strength of the electromagnetic lock is expressed in KG (kg), and the test method is static pressure. The so-called static pressure means that the electromagnetic lock gradually increases the pulling force on the adsorption iron plate after the electromagnetic lock is energized. When the suction force of the electromagnetic lock is exceeded, the adsorption iron plate is instantly pulled away. The data of this pulling force is the pulling force value of the electromagnetic lock. Moreover, the force of the electromagnetic lock and the adsorption iron plate must be face to face and linear pressure (collinear load test), so the suction force of the electromagnetic lock (HoldingForce) is the largest. The adsorption iron plate may be temporarily magnetized due to the magnetic induction of the electromagnet for a long time.

S4A's magnetic lock is a standard qualified product that can meet the above points. If you want more information about S4A, please contact: sales4@s4a-access.com (Rebecca FU )