SEARCH
— 葡萄酒 | 威士忌 | 白兰地 | 啤酒 —
— 葡萄酒 | 威士忌 | 白兰地 | 啤酒 —
On electrical installation or maintenance sites, some electricians can instantly determine the required cable size based on the power, leaving many novice electricians in awe. Today, we’ll delve into the reason behind this.
Let’s examine the power calculation formula for a three-phase asynchronous motor:
P=3×U×I×cos(ϕ)×η
In layman’s terms:
Power = Square root of 3 * Rated Voltage * Rated Current * Power Factor * Efficiency
From this, we can derive the formula for current:
I=P3×U×cos(ϕ)×η
Again, in layman’s terms:
Current = Power / (Square root of 3 * Rated Voltage * Power Factor * Efficiency)
Using this formula, we can establish the relationship between current and power. In the International System of Units (SI), power is measured in watts, not kilowatts. Therefore, to calculate the current for a 4 kW motor, the power should be 4000 W. The typical power factor is around 0.8, and the efficiency is usually 90%. After calculation, we find that the current is approximately twice the power.
Under a 380V three-phase power supply condition, the rated current is roughly twice the rated power. For example, a 4 kW motor would have a rated current of about 8A.
It’s important to remember that the current being twice the power only applies to three-phase, 380V AC asynchronous motors.
My home telecom broadband is 300 Mbps. When I use 2.4G Wi-Fi, the download speed is 7 Mbps, but when I use 5G Wi-Fi, the download speed is 27 Mbps. Is this situation correct? I feel that the download speed within 100 Mbps should be the same.
View detailsHi everyone! I'm Mike from the technical solutions team. Recently, I received several inquiries about powering the SR600 router with solar energy for remote installations. Let me share our comprehensive solution based on real deployment experience.
View detailsA slow internet speed can make life feel like a dark tunnel! WiFi has become an essential part of many people's lives, and internet speed is closely related to personal happiness. However, we often encounter situations where the home WiFi gets slo...
View detailsMo