Photovoltaic Design

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Load Calculation

Solar Array Sizing

Battery Sizing

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Calculation Reference
Photovoltaic Design

Solar Array Sizing

Battery Sizing

With the four given parameters (terminal voltage, terminal resistance, no-load speed, and no-load current), you can estimate the performance of a DC or brushless DC motor by calculating its efficiency, torque, and power output under specific operating conditions.

  1. Terminal Voltage (V)
  2. Terminal Resistance (R)
  3. No-Load Speed (ωo, in RPM)
  4. No-Load Current (Io)

First, let's calculate the motor's speed-torque slope and no-load losses:

  1. Speed-Torque Slope (K): K = (ωo * R) / V

  2. No-Load Losses (P_loss): P_loss = Io * V

Now, you can calculate the motor's performance at a specific operating current (I):

  1. Operating Current (I): Choose a value representing the current under specific operating conditions.

  2. Voltage Drop (V_drop): V_drop = I * R

  3. Back EMF (E): E = V - V_drop

  4. Operating Speed (ω, in RPM): ω = E / K

  5. Operating Torque (T): T = (V - E) * K / R

  6. Electrical Power Input (P_in): P_in = V * I

  7. Mechanical Power Output (P_out): P_out = T * ω * (π / 30) (Convert RPM to rad/s by multiplying by π/30)

  8. Efficiency (η): η = P_out / P_in * 100%

Using these calculations, you can estimate the motor's performance under specific operating conditions. Keep in mind that these calculations are simplified and may not be entirely accurate, as they do not account for factors like magnetic saturation, temperature effects, or complex motor dynamics. However, they can provide a reasonable approximation of the motor's performance and efficiency.

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25 Apr 2023
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Comments: 1
johndoyle[admin] 8 years ago
Providing inspiration for us all. I have extended your XLC Pro subscription by 3 months by way of thanks.
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