12V or 24V DC Motor ? Exploring the Impact of Voltage on Motor Performance?

What is the Voltage of DC Motor ?

How to compare the 12V vs 24V DC motor? Firstly we have to know the voltage of the motor refers to the potential difference of the power input. Also known as the working voltage or the power supply voltage. Within the rated voltage range of the motor, the voltage is the main factor used to drive the rotor of electric motor to rotate.

In general, the rated voltage of the motor refers to the power supply voltage range specified when the motor is designed, and the motor can operate normally and output rated power within this voltage range. If the rated voltage range is exceeded, the motor will be overloaded. Long-term overload operation will cause the motor to overheat and damage the coil inside the motor.

Rated Voltage of DC Motor

Voltage Design : DONCEN will calculate the rated voltage range when designing DC motors. The design of the rated voltage needs to consider the rated power of the motor, the rated speed, and the heat resistance level of the enameled wire. At the same time, short-term overload use should also be considered within the scope of design.

Voltage Range Test : According to the motor design parameters, the load test of the motor can help to confirm the rated voltage range of the motor.

12V or 24V DC Motor ? What is the impact of Voltage on Motor Performance ?

Basic Assumptions

• Rated Current at 12V: 1A
• Rated Torque at 12V: 2mN·m
• Rated Speed at 12V: 3000 RPM
• Voltage at 12V: 12V

Speed is proportional to voltage:

$$
N \propto V
$$
Thus:
$$
N_{24V} = 2 \times N_{12V}
$$

Torque is proportional to current:

$$
T \propto I
$$
Since the load remains unchanged:
$$
I_{24V} = I_{12V}
$$

Power calculation:

$$
P = T \times \omega
$$
where:
$$
\omega = \frac{2\pi N}{60}
$$

---

Calculated Parameters

Rated Power Calculation

At 12V:

$$
P_{12V} = 0.002 \times \frac{2\pi \times 3000}{60}
$$
$$
P_{12V} = 0.002 \times 314.16 = 0.628W
$$

At 24V:

$$
P_{24V} = 0.002 \times \frac{2\pi \times 6000}{60}
$$
$$
P_{24V} = 0.002 \times 628.32 = 2.512W
$$

Thus, power doubles when voltage increases from 12V to 24V.

---

Final Comparison Table

Parameter	12V	24V	Change
Rated Voltage	12V	24V	2×
Rated Speed	3000 RPM	6000 RPM	2×
Rated Current	1A	1A	No change
Rated Torque	2mN·m	2mN·m	No change
Rated Power	0.628W	2.512W	4×

---

Conclusions

• Rated speed doubles when voltage increases.
• Rated current remains the same for the same torque load.
• Rated torque remains unchanged because it depends on current.
• Rated power doubles as speed increases while torque remains constant.

Key Equations

$$
N_{24V} = 2 \times N_{12V}
$$

$$
P_{24V} = 2 \times P_{12V}
$$

$$
T_{24V} = T_{12V}
$$

$$
I_{24V} = I_{12V}
$$

PG36555 24V vs 12V Test Report

The commonly used voltage of micro dc motors is generally 12V or 24 V. Therefore, we choose these two parameters as a voltage comparison.

We choose PG36555 24V Rated rpm 6000 Gear Ratio 1:50.9K Motor as example. We will do motor test under 12V and 24V for a same motor.

Here are the result:

PG36555 Motor: Real vs. Theoretical Performance Analysis

The test data of the PG36555 motor at 12V and 24V show some deviations from theoretical expectations. Here’s a simple breakdown of the differences and the reasons behind them.

Parameter	12V (Measured)	24V (Measured)
Voltage (V)	12V	24V
Speed (RPM)	45.4	103.5
Current (A)	0.72A	0.858A
Power (W)	2.855W	9.751W
Torque (N.m)	0.6N.m	0.9N.m

---

1. Speed Scaling (Slightly Higher Than Expected)

• Theory: Speed should double with voltage →

$$
N_{24V} = 2 \times N_{12V}
$$

• Actual: Speed increased 2.28× instead of 2×

🔹 Why?
✅ Reduced load torque allowed slightly higher speed.
✅ Lower armature resistance drop at 24V.

---

2. Power Scaling (Lower Than Expected)

• Theory: Power should increase 4× →

$$
P_{24V} = 4 \times P_{12V}
$$

• Actual: Power increased 3.42× instead of 4×

🔹 Why?
⚠️ Increased iron losses (eddy currents & hysteresis) at higher speed.
⚠️ Higher windage and friction losses in the motor & gearbox.

---

3. Current Scaling (Slightly Higher Than Expected)

• Theory: Current should stay the same →

$$
I_{24V} = I_{12V}
$$

• Actual: Current increased 1.19× instead of 1×

🔹 Why?
⚠️ More core losses at 24V require extra current.
⚠️ Additional friction & air drag in the system.

---

4. Torque Scaling (Higher Than Expected)

• Theory: Torque should stay the same →

$$
T_{24V} = T_{12V}
$$

• Actual: Torque increased 1.5× instead of 1×

🔹 Why?
✅ Higher efficiency at 24V means better power-to-torque conversion.
✅ Non-linear load behavior may demand more torque at higher speed.

---

5. Efficiency Improvement at 24V

Voltage	Motor Efficiency
12V	33%
24V	47%

🔹 Why?
✅ Less copper loss relative to total power at 24V.
✅ Better torque-to-current ratio.
⚠️ But iron losses increase, limiting efficiency gains.

---

Conclusion: Why Does the Real Data Differ?

Expectation	Real Data	Why the Difference?
Speed 2×2×2×	2.28×	Reduced load torque, lower IRIRIR drop.
Power 4×4×4×	3.42×	Iron, friction, windage losses.
Current 1×1×1×	1.19×	Extra core losses.
Torque 1×1×1×	1.5×	Better efficiency, possible load change.

Final Takeaway:

• 24V operation is more efficient but real-world losses reduce the expected gains.
• Speed & torque perform better than expected, but power and current are limited by losses.

Rated Article

Motor Power: Defination and How to calculate Motor Power

Motor Torque: Definition, How to Calculate Motor Torque

Motor Current Analysis: Definitions and Fundamental Principles