this+problem

это моя книга — that / this is my book

это товарищ Петров — that / this is comrade Petrov

это хорошо — that is good*

я это вижу — I can see that

об этом — about that

после этого — after that

с этим — with that

для этого — for that

от этого — because of that

что это? — what is that?

решить эту задачу — это самое главное — the most important thing is to solve this problem

кто это? — Это его сестра — who is that? — That / it is his sister

это был он — it was he

работа — это для него самое главное — work is the most important thing for him; work comes first with him

дети — это большая радость — children are a great joy

при всём этом — in spite of all this, for all this

что это с вами? — what is the matter with you?

Satisfactory analysis (or assay) can be performed (or made, or done) on these samples.

Blood examination.

This may be determined from an analysis of moonrock.

Test (or Analysis) for alkalinity (or for beryllium)...

Medical tests ( such as specimen analyses)...

Urinalysis (an analysis of urine)...

We shall cover these compounds in the next chapter.

Here we examine the combined effect of...

We shall deal with this subject in the next chapter.

To fully appreciate the significance of these data, each aspect of the genetical processes must first be scrutinized.

The question could be approached from two angles.

In this paper we will not concern ourselves with those problems.

We have considered this problem carefully.

Mechanics treats of the action of forces and their effect.

Since subtraction is the same process as addition, subtraction is not treated separately here.

We will now look at the basic principles used in fluid logic.

Let us take a look at the individual components of...

The formation and properties of shock waves will be discussed in the following chapter.

The effect of these differences on... will be covered later.

At the moment enzyme catalysis forms a separate subject; we shall not take it up here.

The next section takes care of Case 1.

The durability of the material must be viewed from two standpoints - the mechanical and the electrical.

When an object is viewed with both eyes, it looks like...

This series can be considered a result of the substitution of...

Then luminiferous ether could be viewed as an exceedingly subtle gas.

ему́ пришло́сь пому́читься над э́той зада́чей — he had a hard time with this problem, he had to struggle with the problem

Это не актуально. — This is of little importance now / This is irrelevant.

Актуальные международные вопросы — international issues of current importance.

Актуальность этой проблемы вызвана тем, что... — This problem is important (today) because...

актуальные международные вопросы — international issues of current importance

Это не актуально. — This is of little importance now / This is irrelevant.

Актуальность этой проблемы вызвана тем, что _ — This problem is important today because _

виды коррекции коэффициента мощности
-

There are 2 types of power factor correction: fixed or automatic.
Fixed power factor correction consists of inserting, in parallel on the network, a capacitor bank whose total power is provided by the assembly of capacitors of identical or different ratings. The bank is energized by a contactor that simultaneously supplies all the capacitors (a single step).
The inrush current peak, in the case of fixed correction, can reach 30 times the nominal current of the capacitor bank.
An automatic power factor correction system, on the other hand, consists of several capacitor banks of identical or different ratings (several steps), energized separately according to the value of the power factor to be corrected.
An electronic device automatically determines the power of the steps to be energized and activates the relevant contactors.
The inrush current peak, in the case of automatic correction, depends on the power of the steps already on duty, and can reach 100 times the nominal current of the step to be energized.
[ABB]

PFC Types
There are two types of Power Factor Correction - Passive PFC and Active PFC.
Passive PFC uses passive elements like a ferrite core inductor on the AC input. It is very easy to implement in existing power circuits although the power factor is low at 60-80%. The proper AC input voltage (115V or 230V) must also be chosen manually. In addition, significant EMI can still result with a 115V AC source. Of course, a 230V AC source will not have this problem!.
Active PFC, on the other hand, uses a switching regulator with active elements like an IC, FETs (Field Effect Transistors) and diodes to create an active PFC circuit. This circuit allows the power supply to achieve a power factor of up to 95%, significantly reduce harmonics and automatically adjusts the AC input voltage. This means you do not have to manually select the AC input voltage. It works with all voltages from 110V to 240V.
[ http://www.techarp.com/showarticle.aspx?artno=81&pgno=1]

 

Тематики

• компенсация реактивной мощности

EN

• PFC types
• types of power factor correction