When using a core-type current transformer, the number of turns on the primary side of the current transformer should be determined as follows:
(1) ampere-turns of the current transformer design is calculated from the current transformer on the nameplate and ampere turns.
(2) Divide the calculated number of amps by the number of primary currents required, and the result is the number of measurements (must be an integer), ie
Number of turns = design ampere number / required amperage
(3) The number of times the primary line passes through the middle hole of the current transformer is the number of turns on the primary side of the current transformer.
Product Description
SPD Surge Protective Device,Lightning Surge Protector
Surge Protection Device (SPD)
It is a device used to limiting instant surge voltage and discharge surge current, it at least including a non-linear component.
Surge protective Device Model Selection
With the impact of international information flow, the rapid development of microelectronic science and technology, communication, computer and automatic control technology, make the building start to go for high quality, high functional area, formed a new building style-intelligent building. As inside the intelligent building there are lot of information system, <<Building lightning protection design norm>> GB50057-94(2002 vision)(hereafter brief as <<lightning protection norm>>) put forward the relative requirement to install the surge protective device, to ensure the information system safely and stable running.
SPD essentially is a equipotential connection material, its model selection is according to the different lightning protection area, different lightning electromagnetic pulse critical and different equipotential connection position, decide which kind of SPD used in the area, to achieve the equipotential connection with the common earth electrode. Our statement will based on SPD's maximum discharge current Imax, continuous operating voltage Uc, protection voltage Up, alarm mode etc.
As per << Lightning Protection Norm>> item 6.4.4 stipulation "SPD must can withstand the expected lightning current flow and should confirm to the additional two requirements: the maximum clamp voltage during surge across, capable to extinguish the power frequency follow-on current after lightning current across." That is the value of SPD's max. clamp voltage add its induction voltage of two ends should be same with the system's basic insulation level and the equipment allowed max. surge voltage.
SPD for Power Supply System Series Selection Guide
The installation of SPD at each lightning protection zone, according to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category, its insulation withstand impulse voltage level can determine the selection of SPD. According to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category as signal level, loading level, distribution and control level, power supply level. Its insulation withstand impulse voltage level are:1500V,2500V,4000V,6000V. As per to the protected equipment installation position different and the different lightning current of different lightning protection zone, to determine the installation position of SPD for power supply and the break-over capacity.
The installation distance between each level SPD should not more than 10m, the distance between SPD and protected equipment should as short as possible, not more than 10m. If due to limitation of installation position, can't guarantee the installation distance, then need to install decoupling component between each level SPD, make the after class SPD can be protected by the prior class SPD. In the low voltage power supply system, connecting an inductor can achieve the decoupling purpose.
SPD for power supply system specification selection principle
Max. continuous operating voltage: bigger than protected equipment, the system's max. continuous operating voltage.
TT System: Uc≥1.55Uo (Uo is low voltage system to null line voltage)
TN System: Uc≥1.15Uo
IT System: Uc≥1.15Uo(Uo is low voltage system to line voltage)
Voltage Protection Level: less than the insulation withstand impulse voltage of protected equipment
Rated discharge current: determined as per to the lightning situation of the position installed and lightning protection zone.
SP1 Series
Normal Working Conditions
-Altitude not exceed 2000m
-Ambient air temperature:
Normal range: -5ºC~+40ºC
Extend range: -40ºC~+80ºC
-Relative Humidity: 30% - 90% under indoor temperature condition
- At the place without obviously shaking and shock vibration
- Non-explosion danger medium, non-corrosion gas and dust ( including conductive dust)
Classification
-As per Nominal Discharge Current:
5,10,20,30,40,60KA(8/20µs)
- As per Maximum continuous operating voltage:
275V,320V,385V,420V,440V,460V
- As per to poles
1P,1P+N,2P,3P,3P+N,4P
- As per auxiliary functions:
a. With remote signal output ( remote alarm function)
b. Without remote signal output
Selection Principle
- The continuous applied voltage on the two terminals of SPD should not more than the maximum continuous operating voltage Uc value;
- The voltage protection level Up of SPD should less than the maximum impulse withstand voltage of the protected equipment;
- As per to the different earthing system and protection mode to select the specification accordingly;
Product Features
1, built-in over-current overheating, temperature control circuit technology.
2, the module design, easy installation, online replacement.
3, low leakage current, fast response time, low residual voltage.
4, alarm indication device, green (normal) v red (fault).
| Model/Technical Parameters | WR-B60 | WR-B80 | WR-B100 | WR-B120 | WR-B150 |
| Rated Operating Voltage Un (V ~) | 220V 380V | 220V 380V | 220V 380V | 220V 380V | 220V 380V |
| Maximum Continuous Operating Voltage Uc (V ~) kV | 385V 420V | 385V 420V | 385V 420V | 385V 420V | 385V 420V |
| Voltage Protection Level Up (V ~) kV | ≤1.8≤2.2 | ≤2.4≤2.5 | ≤2.5≤3.2 | ≤3.4≤3.7 | ≤4.0≤4.5 |
|
Maximum Discharge Current Imax(8/μ20μs)kA |
60 | 80 | 100 | 120 | 150 |
|
Nominal Discharge Current In(8/μ20μs)kA |
30 | 40 | 60 | 80 | 100 |
| Response Time | <25 | <100 | |||
| L/N(mm²)The Cross Section Of L/N Line | 16,25 | 16,25 | 16,25 | 16,25 | 25,35 |
| PE (mm²)The Cross Section Of PE Line | 16,25 | 25,35 | 25,35 | 25,35 | 35 |
| Fuse or Switch (A) | 63A | 63A | 63A,100A | 63A,100A | 63A,125A |
| The Line Section of Communication and Alarm (mm²) | ≥ 1.5 | ||||
|
Operating Environment-C |
(-40ºC~-+85ºC) | ||||
| Relative humidity 25 ºC | ≤95% | ||||
| installation | Standard Rail35mm | ||||
| Material of Outer Covering | Fiber Glass Reinforced Plastic | ||||
Surge Protector SPD,Surge Protection Device SPD,SPD
Wenzhou Korlen Electric Appliances Co., Ltd. , https://www.zjthermalrelay.com