Understanding the Battery Requirements for a High-Power 3-Phase AC Electric Motor

When it comes to electric motors, especially those designed for industrial or heavy-duty applications, understanding the intricate details of battery requirements becomes crucial. This article will delve into how many 3.6-volt 5Ah batteries are required to power a high-power 3-phase AC electric motor rated at 460 volts and 320 amps. We will break down the process step-by-step to provide a clear and comprehensive explanation.

Step 1: Calculate the Power Requirement of the Motor

The power requirement of an electric motor is calculated using the formula:

P √3 × V × I

Where:

Plugging in the values, we get:

P √3 × 460 V × 320 A ≈ 460 × 320 × 1.732 ≈ 2,545,600 W or 254.56 kW

Step 2: Calculate the Total Voltage Needed from the Batteries

Since the motor operates at 460 volts, we need to connect enough batteries in series to achieve this voltage.

Step 3: Determine the Number of Batteries in Series

Each 3.6-volt battery contributes 3.6 volts. The number of batteries ( N ) needed in series to reach 460 volts is given by:

N 460 V / 3.6 V ≈ 127.78

Since we cannot have a fraction of a battery, we round up to 128 batteries in series.

Step 4: Calculate the Total Current Capacity

Each 3.6-volt battery has a capacity of 5Ah. In a series connection, the current remains the same across all batteries. Therefore, the total capacity from the battery pack in terms of amp-hours (Ah) will still be 5Ah.

Step 5: Determine the Total Current Requirement

The motor requires 320 amps. Since we have only 5Ah from the series connection, we need to connect multiple series strings in parallel to meet the current requirement.

The number of parallel strings ( M ) needed to provide 320 amps is given by:

M 320 A / 5 Ah 64

Step 6: Calculate the Total Number of Batteries

The total number of batteries required is the product of the number of batteries in series and the number of parallel strings:

Total Batteries N × M 128 × 64 8,192

Conclusion: You would need 8,192 batteries of 3.6 volts and 5Ah to run a 3-phase AC electric motor rated at 460 volts and 320 amps.

Real-World Applications: 3-Phase 460 Volt 320 Amp Motor

A 3-phase 460 Volt 320 Amp motor is a massive motor and will typically be powered from the mains or a large diesel generator in cases where it is used in remote quarries away from the mains. This highlights the practical challenges and considerations when dealing with high-power electric motors.