Question about NRS S129 - Starter Solenoid Switch, D984

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A solenoid that is 75 cm long produces a magnetic field of 2.1 T within its core when it carries a current of 6.8 A. How many turns of wire are contained in this solenoid?

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Hi, i'm guessing this is for school
2.1T is the core saturation flux value of iron so you can disregard that ( this is standard for iron cored solenoids )
so your trying to find out the inductive reactance of the coil , the supply voltage and whether it is d.c or a.c ( and the frequency in hertz ( 60Hz for USA mains ) and plug your values into any coil contruction program of which there is many freely available on the net .

Posted on Apr 26, 2010


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How Does an MRI Work

Magnetic resonance imaging (MRI), also known as nuclear magnetic resonance imaging, is a technique for creating detailed images of the human body.
The human body is mostly water. Water molecules (H20) contain hydrogen nuclei (protons), which become aligned in a magnetic field. An MRI scanner applies a very strong magnetic field (about 0.2 to 3 Teslas, or roughly a thousand times the strength of a typical fridge magnet), which aligns the proton "spins."
The scanner also produces a radio frequency current that creates a varying magnetic field. The protons absorb the energy from the variable field and flip their spins. When the field is turned off, the protons gradually return to their normal spin, a process called precession. The return process produces a radio signal that can be measured by receivers in the scanner and made into an image.
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Jul 23, 2016 | Televison & Video


Generator Not Producing Power - Field Winding

There are 4 requirements that have to be met before a generator is able to produce power. Due to number of questions that have been asked, a Coleman PowerMate 1500-1850 with a Briggs and Stratton Engine will be used here.

1) The Engine has to be turning at correct speed
2) Field Winding (Rotor) on the alternator must be energized
3) AC Winding (Stator) must create a voltage in presence of magnetic field
4) Output passes through Safety Devices before it reaches an outlet.

This Tip will cover the Field Winding.

The alternator of the generator is similar to the alternator in your vehicle. A current flows through the field winding, and creates a magnetic field. This magnetic field is rotated (by the engine), and the magnetic lines of force cut through the many coils of wire that are located in the stator.

First things first though. Lets see if the field winding (aka rotor) is any good. You will first have to disassemble the generator / alternator to get to the brushes. The brushes are how the current flows from the regulator, and into the rotor while it is spinning. Look closely, and you will see 2 rings on the rotor. Each ring is the end of the coil of wire that makes up the rotor. Using a multimeter, check for resistance between the rings, but make sure that you don't scratch or gouge them. You should have some kind of continuity here, compare your readings against what is published in the service manual. Also check each ring to the core or rod of the rotor as well. There should NOT be any continuity at all. If there is, this indicates a grounded rotor, and will have to be rewound (starter / alternator shop) or replaced.

Look at the brushes and brush holder assembly. Take a measurement of the length of each brush, and compare it to the minimum length in the service manual. If the brush is too short, or shows signs of overheating, shock, or otherwise, replace the brushes. If the brush holder is also darkened or burnt, it will also need to be replaces as well.

From the brush holder, follow the wires to the voltage regulator. In most low end generators, this is merely a capacitor that samples output voltage, and feeds it back into the rotor. There should also be a diode here as well. Again, using your multimeter, check the diode to see if it is open or shorted. If your meter has a diode check function, use it. Otherwise, check the diode using the resistance scale. You should have a resistance in direction, and infinite (open) in the other. If you have resistance in both directions, or infinite in both directions, then the diode is bad and will need to be replaced. Some meters will have a capacitor check, but the capacitor in the generator will likely be too large for this to work. Look for signs that the capacitor may be bad. Bulging, leaking, damaged terminals all indicate replacement is needed.

On generators that have an actual voltage regulator, you will need to consult the service manual for steps to check the regulator. Usually, regulators are not easily tested, and are replaced when other potential problems have been ruled out.

If a generator has sat for a long time, it may have lost its residual magnetism. When the engine is not turning, there remains a small magnetic field due to the properties of the iron / steel rotor core. It is possible that this field has dissipated over time. You can temporarily reestablish this field through a process called "Flashing." Basically, it involves connecting a lantern-type of battery between one of the brushes, and the core of the rotor. Consult your owners manual for the exact and recommended procedure.

If the field winding is testing good, its time to move onto the next tip:
Stator Winding.

on Jul 15, 2010 | Electrical Supplies

1 Answer

What is a stator plate for keywayhacker 125

Hi, Gerd a stator plate is basically a plate that the stator is secured to, the stator is basically one long piece of thinly insulated wire that wraps around several iron core pieces of metal many times, when a small electrical charge is applied to this wire it causes the iron core pieces to become magnetic, a rotor with very strong whole earth magnets that are affixed to it, rotates over the stator's magnetic field causing it to produce a high amount of AC volts which is then sent to a regulator/rectifier which changes the high AC voltage to low DC voltage which in turn charges your battery, this is what is commonly known as an alternator, this system of passing fixed magnets over a magnetic field has many uses, for example, to make generators and CDI ignitions. I hope this clears up any questions you may have had, for more information about your question and valuable "FREE" downloads that you will need please click on the websites below. Good luck and have a nice day.
Motorcycle Battery Charging System Explained
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How to test and repair the charging system on scooter
PDF Moto Manual

Mar 31, 2016 | Motorcycles

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How do you flash a generator

Flash Your Generac Portable Generator with a Corded Drill ...

? 1:14
Oct 31, 2012 - Uploaded by Generacpowersystems
If your portable generator runs but doesn't produce output voltage, you can use a corded drill to reintroduce ...

Re-energizing Dead Generators - End Times Report
Follow these steps to flash the generator: Plug the electric drill into the generatorreceptacle. (Cordless drills do not work) If the drill is reversible, move the direction switch to the forward position. Start the generator. While depressing the trigger on the drill, spin the drill chuck in reverse direction.

Generator flashing
To restore the small amount of residual magnetism necessary to begin voltage buildup, connect a 12 volt battery to the exciter field while the generator is at rest, as follows: Remove exciter field leads F+ and F- from the voltage regulator.

Flash A Generator - Davidson Sales Co Power Generation .

Jan 11, 2016 | Electrical Supplies

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How to make a transformer? What is the principle under it?

Do you mean an electrical transformer? You are far better off to buy one unless it is a special project. Constructing an efficient transformer is fiddly in the extreme.

The principle is that an alternating current (AC) voltage applied to a conductor will generate a fluctuating magnetic field around that conductor. The opposite also applies: a conductor in such a magnetic field will experience an AC current generated in it.

A transformer usually has 2 such conductors coiled around a common core, which intensifies and spreads the field. The voltage on the output side is controlled by the ratio of the 2 coiled conductors, or windings. So a transformer with 2000 windings on one side and 100 on the other has a ratio of 20:1. If a voltage of 240 VAC is applied to the first winding, a voltage of 12 VAC will appear on the other.

For calculation purposes the power is the same on both sides, so that lowering the AC voltage through a transformer implies raising the current at the same time, which can be handy. Therefore a transformer will often be rated by wattage, and input or output voltage. Note that a pure transformer will not work with or produce DC voltages, extra circuitry is required.

Dec 10, 2015 | Exercise & Fitness

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I have a 2001 CAT 420D IT that I just took out of storage after a year. I had the batteries in my basement, charged them, changed the fuel filters and she fired right up. I went out last night to run it...

yes there are a fuse, However i believe that you have problem with your system load. see the chart troubleshooting and fix it.
God bless you

The alternator has a centrally rotating set of coils powered from the field terminal. As this rotor turns, it drags a magnetic field past the stationary coils that surround it.
This magnetic field generates alternating current within these stationary coils, which then passes through a grid of one-way valves (diodes) to produce the DC current useful to automotive applications.
The voltage output is governed by the amount of current in the field circuit, and is controlled by the Voltage Regulator. Current is fed to the battery and other power absorbers through the large Bat terminal on the back of the alternator. A ground connection on the alternator case completes the electrical circuit. There is also a Stator terminal on the alternator, but it is not used on the 427SC. The battery power comes from a connection on the starter solenoid.
Power flows from the ignition switch, through a fuse, to the voltage regulator. Voltage is measured from this source. Internal circuits take the power source and regulate it, sending it to the field terminal of the alternator so that the output voltage to the battery is correct.

Oct 30, 2013 | Cars & Trucks

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71' pontiac ventura, straight 6 250ci., how to wire the starter???

Hi Contact, You will need a low resistance (thick) cable from the battery to the starter motor. The cable fits onto the switching side of the solenoid (the heavy or large terminal of which there are two) The other cable goes into the starter motor. On the solenoid you will also see connections for two small cables. One is chassis ground and the other is from the ignition switch. The solenoid is basically a heavy duty relay. It has a throw in coil and a hold in coil. When these are activated by passing currant through them, they create a magnetic field, pulling a plunger into its center. The plunger is attached to a bus bar which carries the heavy amps which drive the starter motor. The starter has a field coil and an armature. When voltage is fed into the field coils it creates a circuit, passing through the field coils and via the brushes and commutator into the armature, through the winding and back to ground to complete the circuit. It too creates a magnetic field which spins the armature. Centrifugal force throws the Bendix forward, which engages into the ring gear and spins the engine. I don't know if you wanted to know that, but if you understand how something works its much easier to fix it. Best regards John

Sep 09, 2012 | 1998 Buick Century

1 Answer

Cant find wer the spark plugs for a 2001 hyundia sonota

Could be a cover over the spark plugs or plugs have coil on plug system: Ignition System WARNING
To avoid personal injury and/or vehicle damage, refer to the service precautions at the beginning of this section.
General Information NOTE: For information on understanding electricity and troubleshooting electrical circuits, please refer to chassis electrical.
Coil on Plug (COP) System
The coil over plug system was developed so that spark and spark timing could be better controlled on an individual cylinder basis. Each cylinder has an ignition coil mounted directly above the spark plug on the cylinder head cover. A short suppresser/connector replaces the spark plug wire and links the coil to the plug. There are different methods used for primary triggering. Some manufacturers use a combination coil/module, which means each coil has its own control circuit that is activated by the PCM. Others use remote mounted modules to trigger the coils.
Each individual coil is allowed to saturate while all other cylinders fire. For a V-8 engine, this allows a period of seven firing events for coil saturation, compared to three events for the same V-8 engine with a waste spark system. The coil over plug system also benefits from a minimum amount of energy lost, due to the resistance of spark plug wires.
Distributor System
If a distributor is not keyed for installation with only one orientation, it could have been removed and installed improperly and then rewired. The new wiring arrangement would maintain the correct firing order, but could change the relative placement of the plug towers in relation to the engine. For this reason it is imperative that you label all wires before disconnecting any of them. Also, before removal, compare the current wiring with the accompanying illustrations. If the current wiring does not match, make notes of the current plug wire locations and orientation of the distributor cap.
Magnetic Sensor / Pick-Up Coil
The magnetic sensor in electronic ignition system is made up of a small coil of wire wrapped around an iron core, a permanent magnet and a toothed wheel called a reluctor. These sensors can be found mounted in a distributor, or at the front, middle, or rear of the crankshaft or camshaft, and are two-wire sensors.
The permanent magnet produces a magnetic field that passes thru the center of the pick-up coil. As the reluctor turns, the small teeth enter the magnetic field. Because the metal is a better conductor for the field than the air between the magnet and reluctor, the field strength begins to increase and reaches its maximum when the reluctor teeth are closest to the sensor. An increase in magnetic field induces a positive voltage to the module. As the teeth leave the magnetic field, the decrease in pole strength induces a negative voltage into the module. This alternating positive and negative voltage causes a small AC current. This alternating current after passing through an analog/digital converter is used by the module or engine controller to trigger the primary circuit.
Hall-Effect Device
Another device that can be used to create a triggering signal is a hall-effect device. A hall-effect device can be thought of as a solid-state On/Off switch. The hall-effect switch is a three-wire device that must receive a power and ground. The hall-effect switch is used in conjunction with an interrupter ring with a series of slots or openings cut into it. Depending on the application, these slots are spaced around the ring in a specific configuration. As the ring rotates, the slots pass between the hall-effect switch, and alternately turns the voltage off and on. When a slot aligns with the hall-effect switch, the controller sees voltage on the signal line. When the area between slots passes the hall-effect switch, the signal is pulled low. This results in a voltage of 0V–0.1V at the controller.
The rotation of the interrupter ring causes the signal to toggle, which causes a continual series of digital pulses on the signal line. This digital pulse is the timing signal that is used by the ignition module or engine computer to open and close the primary circuit. The controller processes these pulses as the RPM signal.
Another device used to create a triggering signal is the photo optical sensor. Inside the distributor, there are pick-ups called the Reference pick-up and the Sync pick-up. Each pick-up has a Light Emitting Diode (LED) and a phototransistor. A slotted disc rotates between the pick-ups. The pair of LED’s and phototransistors generates crankshaft position and RPM signals (high and low-resolution signals). The LED’s are powered by a 9- or 12-volt source (depending on manufacturer). Each phototransistor is used to turn a 5-volt signal from the engine controller on and off.
If we look at the optical distributor used in the Chrysler 3.0L engine as an example, there are two areas of slots cut into the disc. The outer diameter of the disc, which generates the high-resolution signal, contains 350 slots. Each of these slots represents 1 degree of crankshaft rotation. An area of approximately 3/8" with no slots represents the remaining 10 degrees. The inner portion of the disc is the low-resolution signal and contains six 60-degree slots. Each of these slots represents the piston’s top dead center position for each cylinder. The controller uses the high-resolution signal to regulate spark timing up to 1200 RPM. This ensures timing accuracy, since crankshaft speed fluctuations are most likely to occur because of the firing pulses during cranking and idle. The low-resolution signal is used for injector firing, as well as ignition timing above 1200 RPM.
As the slots pass between the LED’s and the phototransistors, the transistors are toggled on and off. This occurs as the light beams from the LED’s are alternately interrupted. When the light beam from the LED strikes the phototransistor, the transistor turns on. This causes the 5-volt signal to be pulled low (0V–0.1V). When the rotating disc blocks the light beam, the transistor turns off. This causes the 5-volt signal to remain high.
Ignition Coil
The heart of the automotive ignition system is the ignition coil. The ignition coil is a step-up transformer, since it boosts battery voltage to the high voltage that is necessary for proper combustion.
The ignition coil consists of a primary winding and secondary winding wrapped around a soft iron core. The primary winding is made up of several hundred turns of heavy wire, while the secondary winding consists of thousands of turns of fine wire. The iron core is used to conduct magnetic lines of force efficiently.
When current flows through the primary winding, a magnetic field is created. The more time current is permitted to flow, the stronger the magnetic field becomes. When the current is turned off, the magnetic field collapses causing a high voltage to be induced in the secondary winding through the process of induction.
A few hundred volts will be generated in the primary winding because of the collapsing magnetic field across the heavy primary wire. However, as the magnetic lines of force cut across the thousands of turns of fine wire in the secondary, a far greater voltage is produced. The production of primary voltage is called self-induction, since the primary winding essentially magnifies its own initial voltage when the magnetic field collapses.
Related Symptoms
Faulty ignition system components along with loose connections, bad grounds, high resistance or opens in the circuit, may cause the following symptoms:
  • No start condition
  • Stalling after cold start
  • Stalling after hot start
  • Surging off idle
  • Extended crank time when engine is cold
  • Unstable idle
  • Running rough during off idle acceleration
  • Bucking
  • Hesitation
  • Stumble
  • Poor fuel economy
  • Spark knock

Jul 08, 2010 | 2001 Hyundai Sonata

1 Answer

System is only charging at 13.8v max instead of 14.2~14.8v, There is some corrosion inside the wires and many of the wire plugs have corrosion. Would this bit of corrosion inside the wires have enough...

Ok, the charging system works like this:

The voltage Regulator/Rectifier unit takes battery power and sends it to the alternator rotor via the brushes in the cap. The brushes are carbon based, and spring loaded and press against the face of the rotor, such that they are compressed when the alternator cover is tightened. If the brushes are worn away or if the commutator rings (concentric copper circles on the rotor) are dirty, or if there is damage to the wires or if the Regulator half of the R/R unit is defective or if there is a problem with the positive wire between the battery and the R/R, then no power gets to the field coils in the rotor.

Normally, when everything is working properly, a voltage is applied to those field coils, energising them into electromagnets. The strength of the
magnetic field varies in direct proportion to the voltage applied by the
Regulator half of the R/R unit.

When the battery voltage drops a bit, the R/R unit sends more power to the field coils, making the magnetic field stronger.

The rotor spins inside the stator coils. There are 3 separate loops wound
around each other in the stator, and each loop is tapped with a white wire
that leads off to the R/R unit. The spinning magnetic field of the rotor
induces a current in the stator windings. The stronger the magnetic field,
the greater the induced current (the rotational speed of the rotor also
influences the output strength). The 3 loops interact, such that each acts as the ground circuit for the other two in turn, producing a 3-phase
alternating current, 120 degrees apart.

Each of the 3 white wires leads to a pair of diodes inside the Rectifier
half of the R/R unit. There are two connectors along this path -- one is
behind the battery box, as previously described. The other is near the R/R
unit and includes the Red wire to the battery. Any corrosion on any of these high-current carrying wires will impede the current flow, and often heat the connector to the point of melting the plastic.

Diodes are like electrical check valves -- they only allow current to flow
in one direction. In this way, the 3 AC current sources are converted to DC and merged. From there, the resulting current is passed to the battery via the red wire.

So, when everything is working properly, the battery sits at around 12.5 to
13v with the engine off. Turning on the key drops that slightly because of
the draw caused by lights, etc. Hitting the start button drops that by a
couple of volts as the starter draws massive current. Once the engine
starts, the Alternator sends current down each of the 3 white wires, and the voltage picks up to about 14.5 volts at around 2,000 rpm.

One of those white wires is tapped by the headlight relay and the computer. When the alternator starts producing power, the voltage on that white wire latches the relay and tells the computer to start it's check cycle.

Because the white wires are isolated by the diodes in the R/R unit, no
outside voltage (from the battery or a charger or another vehicle used to
boost the system) can fool the relay or the computer. The only way to
trigger them is for the alternator to produce AC power on that white wire.

After checking the condition of the connectors and wiring (unplug the R/R
and meter the whole thing, wire by wire, back at the alternator stator), you could (after charging the battery) start the bike and back-probe (ie insert one of the probes in the back of the connector, such that it contacts the metal conductor inside) each of the 3 white wires with a voltmeter set to 50v AC.

If the voltage one is significantly lower than the others, then you likely have a problem with the stator or the R/R. Follow the diagnostics in the manual to rule out the R/R. If you have no (or little) voltage on all, then I'd suspect the brushes, feild coil windings or wires between the R/R and the brushes. (assuming the regulator passed muster).

Oct 17, 2009 | 1986 Yamaha XJ 700 X Maxim

1 Answer

Won't start

82059263 The [PG] starter motors are [non-]repairable starter motors. They have pole pieces that are arranged around the armature within the starter housing. When the solenoid windings are energized, the pull-in winding circuit is completed to ground through the starter motor. The hold-in winding circuit is completed to ground through the solenoid. The windings work together magnetically to pull in and hold in the plunger. The plunger moves the shift lever. This action causes the starter drive assembly to rotate on the armature shaft spline as it engages with the flywheel ring gear on the engine. At the same time, the plunger closes the solenoid switch contacts in the starter solenoid. Full battery voltage is then applied directly to the starter motor and it cranks the engine.

As soon as the solenoid switch contacts close, current stops flowing thorough the pull-in winding as battery voltage is now applied to both ends of the windings. The hold-in winding remains energized; its magnetic field is strong enough to hold the plunger, shift lever, starter drive assembly, and solenoid switch contacts in place to continue cranking the engine. When the engine starts, the pinion gear overrun protects the armature from excessive speed until the switch is opened.

When the ignition switch is released from the START position, crank voltage is removed from the starter solenoid S terminal. Current flows from the motor contacts through both windings to ground at the end of the hold-in winding. However, the direction of the current flow through the pull-in winding is now in the opposite direction of the current flow when the winding was first energized.

The magnetic fields of the pull-in and hold-in windings now oppose one another. This action of the windings, along with the help of the return spring, cause the starter drive assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter motor is turned off.

Here is the wiring circuit for the NEUTRAL SAFETY SWITCH which is what I believe to be your problem, do the reverse lights come on when the keky is ON and the transmission selector is in REVERSE? IF NOT you have a renge selector problem.
if you find this information helpful please give me a good rating and please contact me if you need any further assistance.
Thank you, Randy

Jul 13, 2008 | 2000 Chevrolet Venture

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