Advice 1: How to determine pole

Magnets, electromagnets, DC voltage and devices with double-sided conductivity have two poles. In the first case, these poles are called North and South, and the second negative and positive.
To determine the poles of the magnet, take the second magnet, where the poles are marked with letters (N - North, S - South) or colors (red - North, green, blue or grey - South). The North pole of a test magnet will attract to the South of the subject and Vice versa. Test and test magnets should be about the same strength, or maybe switching the one that is weaker. When handling strong magnets be careful not to mechanical trauma of the fingers.
To determine the polarity of the rectifying element unilateral conductivity connect an ohmmeter first in one and then in the other polarity. The element should be de-energized. If the probe, on which there is a negative voltage will be connected to the cathode, and the probe with a positive voltage to the anode, the device shows a resistance significantly less than infinity. From analog devices the polarity of the voltage in ohmmeter mode, usually the opposite of the polarity of the voltage that should be applied to the same probes using a voltmeter. Digital devices of the same polarity, these often coincide. If in doubt, check your meter on diode, the pin of which is known.
To determine the poles of the DC voltage source, connect a voltmeter, which previously exhibited the appropriate limit. If the source generates a voltage more than 24 V to comply with safety rules. The probes of the voltmeter have the following colors: black or blue is negative, white or red plus. Analog voltmeter with polarity arrow will deviate slightly to the left and you hit the limiter, and digital - on the indicator before the number will appear a minus sign. Note that if incorrectly chosen the limit force applied to the arrow, may be so great that the latter will bend down.
Pole of the electromagnet define in the same way as the poles of the magnet. When changing the polarity of the mains voltage, they will be swapped. If the magnetic coil is wound in a clockwise direction, the negative output will correspond to the North pole, while the positive South. The electromagnet winding is wound counterclockwise, according to the conclusions of the polesm opposite. Even if the coil is powered by low voltage, beware of pulses of self-induction arising at the moments of interruption of the current.

Advice 2: How to repair magnets

Over time magnets lose their properties, although this may occur over decades. In addition, magnets can be accidentally deprive properties when heated to a certain temperature. In any case, if their actions depends on the work of, for example, motor boats, sometimes it's easier to recover the magnets, than to buy a new one.
You will need
  • – a magnet or a blank of electrical steel or a ferrite;
  • – wire of PEV;
  • thin copper conductor 0,05;
  • – fuse Meringue;
  • – AC or DC;
  • – high voltage battery or battery;
  • – capacitor;
  • – powerful magnet.
If you want to get properties of the magnet in the internal combustion engine, first remove the base of the magneto, the ignition coil and remove the iron tip. Install the magnet on the corner of the table, remote from large metal objects and radiators.
Wrap over the core 500-1000 turns of wire of PEV in diameter of 0.1-0.8 mm in a time frame. If you need to magnetize a horseshoe-shaped core, the winding to produce in the bend magnet, or divide it into two halves and move to different poles.
The ends of the windings connect with thin copper conductor, of a thickness not exceeding 0,05 mm. connect the magnet through the conductor in a network of DC or AC or high-voltage battery (battery). Instead of a thin conductor to ensure the safety, you can use the Bose fuse in a glass tube.
Be careful at the time of passage of current, since the magnet when it is magnetized, and the conductor is burned (melted), and its spray can get into eyes and skin. Try to stay away from construction, keep the children and animals.
Gather the following installation: the coil in 50-200 turns and inside her former magnet or any blank of electrical steel and the coil dimensions must be 30-40% more than the size of the magnet. Orient the magnet in the desired direction relative to the field in the coil: either perpendicular or along the surface. Then charge the capacitor with a capacity of at least 5,000 microfarads and discharge it into the coil. To activate the system, use the push button switch: "charge" capacitor "discharge" through the coil.
A little to restore the properties of the magnet (temporarily), place it near a powerful current magnets with the correct polarity. After a month, assess the condition of the magnet – it will work much better.
Do not work under tension. Beware of mechanical injuries.
Useful advice
The Earth's geographic North pole corresponds to a magnetic South, and Vice versa. The compass of the pole, indicated on the arrow correspond to its magnetization.
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