Energy-Saving And Environmentally Friendly Three-Phase Dry
Isolating Transformer
Overview
Isolation transformers are divided into single-phase (DG) and
three-phase (SG) series. The main function is to isolate electrical
equipment from the grid. It is used for safety occasions or
anti-interference (mostly D/Y, D/Yn △/Yo Or Yo/ △ connection) where
there is no direct electrical connection between the electrical
equipment and the power supply. It is widely used in places such as
subways, high-rise buildings, airports, stations, wharves,
industrial and mining enterprises and tunnels for power
transmission and distribution, as well as the use of import and
export equipment.
SG series three-phase dry-type transformers (380V transformers) are
mainly used to control power and power supply for various high and
low voltage complete sets of electrical, import and export
equipment, precision machine tools, UPS, electroplating, lighting,
heating, communications, chemical and other industries.
The main technical parameters
| Input voltage | rated voltage ±10% |
| Output voltage | rated voltage ±5% (no load) |
| Effectiveness rate | ≥ 95% |
| Waveform distortion | No additional waveform distortion |
| Function | With input voltage, output voltage, current and other indications |
| Protection | With over-current protection, continuous unattended work |
| Insulation resistance | ≥50M ohm |
| Electric strength | Power frequency sinusoidal voltage 2000V for 1 minute without
breakdown or flashover |
| Overload capacity | Twice the rated current for 1 minute |
| Ambient temperature | -15℃––+40℃ |
| Altitude | ＜1000M |
| Relative humidity | ＜95% |
product material
1. Core material:
The core materials used in transformers are mainly iron sheets, low
silicon sheets, and high silicon sheets. The addition of silicon to
the steel sheets can reduce the conductivity of the steel sheets
and increase the resistivity. It can reduce eddy currents and
reduce losses. We usually call silicon-added steel sheets as
silicon steel sheets. The quality of the silicon steel sheets used
in transformers has a great relationship. The quality of silicon
steel sheets is usually expressed by the magnetic flux density B.
Generally, the B value of black iron sheets 6000-8000, low silicon
wafers are 9000-11000, high silicon wafers are 12000-16000,
2. The materials commonly used for winding transformers are
Enameled wire, sand-bag wire, silk-covered wire, commonly used
enameled wire. The requirements for the wire are good electrical
conductivity, sufficient heat resistance of the insulating paint
layer, and certain corrosion resistance. Generally use Q2 type
high-strength polyester enameled wire.
3. Insulation material
In the winding transformer, insulating materials are used for the
isolation between the coil frame and the winding between the
windings. The general transformer frame material can be made of
phenolic cardboard, and the layers can be isolated by polyester
film or telephone paper. Yellow wax cloth can be used for
isolation.
4. Impregnation material:
After the transformer is wound, the next step is to impregnate the
insulating varnish, which can enhance the mechanical strength of
the transformer, improve the insulation performance, and extend the
service life. Under normal circumstances, cresol varnish can be
used as the impregnating materia
There are two main benefits of using an isolation transformer
One is safety. The AC mains (220V single-phase) we use is connected
to the earth with its neutral wire, and there is an AC voltage of
220V between the live wire and the earth. People stand on the
ground, so they have the same potential as the zero line. If people
touch the live line, they will get an electric shock. The secondary
of the isolation transformer is not connected to the earth, and its
output is "floating". When a person touches any line of the
secondary of the isolation transformer, since it cannot form a
current loop, there will be no electric shock, so it is safer. The
same is true for the power line of the three-phase four-wire
system. But it should be noted that if you touch the two secondary
wires at the same time, you will get an electric shock! Therefore,
the isolation transformer does not guarantee safety, and you must
always follow the safety regulations.
The second is to prevent the pollution of power electronic devices
to the power grid. The transformer has a greater attenuation effect
on high-frequency harmonics, so it can prevent the power electronic
equipment from polluting the power grid. Of course, the reverse is
also true. The noise of the power grid will also be isolated by the
isolation transformer to avoid interference to the secondary-side
electrical equipment.
Note
There is no gas vapor, chemical deposits, dust, dirt and other
explosive and corrosive media that seriously affect the insulation
of the transformer at the installation site.
