synchronous generator, the AC side of the rectifier is connected with
capacitors delta connected. The function of these capacitor are (
).
A: resistance-capacitance protection of rectifier
B: compensate the generator terminal voltage change caused by the change
of load current
C: compensate the generator terminal voltage change due to load current
phase change
D: accelerated voltage built-up process
举一反三
- The voltage meter and current meter on the main switchboard shows ( <br/>). A: phase voltage and phase current of generator B: line voltage and line current of generator C: line voltage and line current of crane D: line voltage and line current of shore power
- 100%<br/>Protection for generator stator single phase earth fault() A: zero<br/>sequence voltage protection B: third<br/>harmonic voltage protection C: zreo<br/>sequence current
- The no-load character of a 3-phase synchronous generator is the relationship between ( ). A: no-load emf Eo; exciting current If B: output<br/>voltage U; load current I C: output current I; exciting current If D: no-load<br/>emf Eo; load current I
- The inductor voltage phase lags its current by 90 o, and the capacitor current lags its voltage by 90 o, is this conclusion true? [ ]. A: It's impossible. B: When the capacitance and inductance are nonlinear components. C: When inductance current and voltage, capacitance current and voltage are not related direction. D: Whenever.
- For a balanced three-phase △ -connected load, the average power absorbed by the load is P . Change the △ -connected load to Y-connected load, the power will :
内容
- 0
In contrast to general-purpose CPUs, microcontrollers may not<br/>implement an external ( ) or<br/>data bus. A: voltage B: current C: address D: resistance
- 1
The<br/>common-base amplifier has _()()()__. A: voltage gain, current gain, and power gain B: voltage gain and power gain, but no current gain C: current gain and power gain, but no voltage gain D: current gain and voltage gain, but no power gain
- 2
Which<br/>of the following is not a change in accounting principle? () A: A<br/>change from LIFO to FIFO B: A<br/>change in estimated salvage value of depreciable asset C: A<br/>change from an accelerated depreciation method to straight-line<br/>depreciation D: A<br/>change from historical cost to fair value accounting.
- 3
It is not physically(实际上) possible to have a function(函数) (either voltage or current) change a specified amount (一个特定的量)in zero time.
- 4
Two electronic devices are connected in series. When the load device wants to get the maximum ( ), the impedance of that is the same as the output impedance of the source (front-stage) device. A: Current B: Voltage C: Resistance D: Electric power