Electro-mechanical oscillator or mechanical inverter is an old stuff used for high power inverters to convert DC to AC.As its name shows its difference from static inverters is it have a moving mechanical part that continuously oscillates which reason for pulse or continuous ON-OFF through the circuit.
In the circuit you can see the circuit arrangement of a mechanical inverter. A primary coil is wound over an iron core and its one end is connected to the negative terminal of the power supply and the other to the positive terminal through a series moving arm. When the circuit is charged the primary coil energies and the magnetic field by coil makes the core an electromagnet, thus it pulls the moving arm and the circuit open. As the circuit disconnects the arm return to the initial position as the core looses magnetic field, the return of arm to initial position complete the circuits and this process continues .As a result the arm oscillates in the rate of charging and discharging time of the coil. This oscillation in the primary coil induces an electromotive force in the secondary.
The output of this type of transformer are not pure sine wave and they are not efficient like normal static electronic inverters also it will be very noisy and comparing to other type of inverter power loss is very high.
If we ignore the moving arm arrangement the remaining portion is a normal transformer. The magnitude of secondary voltage and current depends on transformer specifications as like a normal transformer, but depends the wave shape as it is distorted or of spikes also the frequency of oscillation. Consider in terms of time the output wave depends upon inductor time constant (consider primary as an inductor) because secondary emf induces only due to changes in the flux of primary. Here, unlike from a sine wave the coil is only always switching from OFF state to ON state, so if the charging and discharging time interval is high, the flux will be nearly constant, for constant flux no emf induces in the secondary and such state will have a zero emf.
By arranging an apparatus as in the circuit to an unlaminated transformer or a separate core we can simply construct an inverter like this. If the secondary is removed and place a drum on arm contact or extent arm to a drum we can convert this to an electrical alarm by taking advantage of its noise or oscillation.
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| Harmonic oscillator |
The output of this type of transformer are not pure sine wave and they are not efficient like normal static electronic inverters also it will be very noisy and comparing to other type of inverter power loss is very high.
If we ignore the moving arm arrangement the remaining portion is a normal transformer. The magnitude of secondary voltage and current depends on transformer specifications as like a normal transformer, but depends the wave shape as it is distorted or of spikes also the frequency of oscillation. Consider in terms of time the output wave depends upon inductor time constant (consider primary as an inductor) because secondary emf induces only due to changes in the flux of primary. Here, unlike from a sine wave the coil is only always switching from OFF state to ON state, so if the charging and discharging time interval is high, the flux will be nearly constant, for constant flux no emf induces in the secondary and such state will have a zero emf.
By arranging an apparatus as in the circuit to an unlaminated transformer or a separate core we can simply construct an inverter like this. If the secondary is removed and place a drum on arm contact or extent arm to a drum we can convert this to an electrical alarm by taking advantage of its noise or oscillation.
