electric energy meter Rationale

The DC circuit is called reverse into AC inverter circuit. In certain cases, the same set of thyristor rectifier circuit can make, but for the inverter.

The converter operates in inverter state, if the CNC Electric‍ converter is connected to the AC side of the AC power to DC to AC inverter with a frequency counter to the grid to go, called active inverter. If the change is not the AC side current grid connection, but directly to the load, which converts DC to a certain frequency or adjustable frequency alternating current supplied to the load, then called passive inverter. AC frequency control is the use of this principle. Except for the DC reversible active inverter speed control system, but also for AC induction motor rotor Rao line cascade control and other aspects of HVDC.

2 relative concept

Convert alternating current to direct current approach is rectified; and convert DC to AC inverter method.

Rectification, full-wave rectifying circuit is the use of one-way conduction of the diode characteristics, with four diodes connected into a bridge rectifier circuit, the input terminal is an AC power transformers‍ current, the waveform is a sine wave, the direction of the alternating current, and an output terminal waveform current becomes the same direction, and then through a filter circuit to obtain a DC waveform after filtered.

Voltage stabilizer Inverter Classification

Source inverter also has passive inverter. For example, the DC voltage, through a simple, single-phase thyristor bridge type H, H is the output of the cross on each of the four H's vertical thyristor, No. 12, at 34, 14 and 23 were opened to give a positive negative separated the output voltage and current.

The pulse width modulation inverter technology

Basic square wave inverter circuit is simple, AC Contactors‍ but the output voltage waveform harmonic content is too large, but also both the THD (current harmonic distortion) is too large; the phase shift of multiple superimposed small harmonic content inverter output voltage waveform, That THD is small, but the circuit is more complex. The PWM pulse width modulation inverter, both the computer's circuitry, and the output voltage waveform, which has been widely used.

The so-called PWM technology (Pulse Width Modulation, PWM), is made of a reference wave (usually a sine wave, sometimes with a trapezoidal wave or injected zero sequence harmonic sine wave or square wave, etc.) for the modulation wave (Modulating wave), and to N times the frequency of the modulation wave of the triangular wave (sawtooth wave is also sometimes used) of the carrier (Carrier Wave) waveform comparison, the modulation wave is greater than the carrier portion to generate a set of equal amplitude and a width proportional to the modulated waves equivalent rectangular pulse sequence is used to modulate the wave instead of using analog switch, and through the inverter power switch on / off control, the DC power into AC power, this technique is called pulse control inverter technology. Because triangular air circuit breaker‍ carrier wave (or sawtooth) vertical section is a linearly varying degrees, so this technique is called pulse control inverter technology. Since the triangular carrier wave (or sawtooth) is vertical width is linear, so that this modulation is linear, when the modulation wave is a sine wave, a rectangular pulse width of the output pulse train changes sinusoidally, this modulation technique typically also known as the sinusoidal pulse width modulation (Sinusoida PWM) technology.

Inverter FAQ

u outside interference

The inverter may be due to a number of occasions in the strong electromagnetic interference, such as motors, power inverter, a strong magnetic field in the vicinity.

Far away from the device similar to the above.

u inverter does not respond

1. Battery and the inverter is not connected, reconnect.

2. Battery pole reversed, the fuse is blown. Replace the fuse.

u output voltage is low

1. Overload, load current exceeds the Circuit Breakers‍ nominal current, turn off some of the load restart.

2. Input voltage is too low. Ensure input voltage is within the nominal voltage range.‍

u low voltage alarm

1. The batteries need to be recharged.

2. Battery voltage is too low or bad, recharge, check the battery terminals, or with a dry cloth to clean the terminals.
u no the inverter output
1. Battery voltage is too low Air circuit breaker to recharge or replace the battery.
2. Load current is too high, the closure of some load restart inverter.
3. Inverter over-temperature protection. Let inverter cool for some time, and well ventilated place.
4. The inverter fails to start, restart.
5. Terminals reversed, the fuse is blown, replace the fuse.
u inverter does not work
Check the power switch, fuses and battery cable or cigarette lighter.
Inverters DC input
The reason of such failure often happens is the battery is not connected properly, positive and negative terminals of the inverter must be connected correctly and battery positive and negative, positive then positive, then negative negative, right after connecting the switch is closed, basically you can solve such malfunction.
Inverter input and output fuse
Such failures are generally apparent power transformers that, as long as you can replace the fuse.
Battery voltage is higher than the nominal DC input voltage of 20%
The inverter has an operating voltage range, typically rated DC voltage of + -10%, should the higher the voltage, the need to replace batteries or replace the inverter in order to prevent damage to the machine.
Battery voltage is lower than the nominal DC input voltage of 15%
Such problems are mainly due to lack of battery power, you can just give the battery pack.
Load power is too large
Such pre-load problem is caused by lack of power calculation, you need to increase or decrease the power inverter to power the load.

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Explore the direction of protecting the transformer power parity method

Power transformer protection is an important direction of backup protection of transformers. As adjacent components and the internal fault transformer backup protection plays an important role in preventing the expansion of the scope of the failure to ensure the safe operation of the system. Primary and secondary wiring secondary wiring, voltage transformer secondary wiring and protective devices has its  electric meter  relationship correctness, and current transformer, which in actual operation, it is easy due to the wiring polarity errors The misoperation or refuse to move. This paper attempts to explore the direction of power protection, summed up in a simple and reliable method of calibration. The results show that by  air circuit breaker the actual failure of the power system, combined with CT, PT wiring polarity analysis can simply and reliably protect the correctness of power direction direction can be tested, given the equipment acceptance and routine inspection work, which greatly simplifies the work amount.

When charging the transformer should put all protection, and to ensure there is sufficient sensitivity

When charging the transformer should put all protection , and to ensure there is sufficient sensitivity , taking into account the impact of inrush current protection system . To ensure the stability of the system , if necessary, reduce the charge should be preceded by the relevant line of active power. Large current grounding system before charging or transformer outage must be neutral grounding blade closed. After charging , check the supply voltage, so that each side of the voltage transformer does not exceed 5% of the corresponding tap voltage . When the transformer into operation , should be less affected side of the inrush current power transmission . Generally start charging power supply side , after closing the load side switch. When a power outage , you should pull the load side of the switch, pull the power supply side of the switch. If 220kV transformers high and low pressure  mcb circuit breaker , when power by charging high side and low pressure side of the tie should be on the low side splitting power outage . When the ring transformer operating system , you should select the correct charging terminal to reduce the voltage difference tied at . When the transformer parallel operation , shall comply with the conditions of parallel operation . Transformers stop, when an impact  power transformers  as when the power would run the system transformer neutral grounding , protection must be adjusted according to the requirements of operating procedures in the adjustment process, should be fit after pulling principles. For stop after power operation in hot standby transformer neutral point grounding blade should close the state.