# FPV Motor Timing, Demag Compensation, and PWM Frequency Tuning Guide
Your ESC does more than spin the motor. It controls exactly when each electromagnetic field energizes — and motor timing, demagnetization compensation, and PWM frequency are the three settings that determine how efficiently that happens. Get them wrong, and you lose power, overheat motors, or destroy ESCs. Get them right, and your quad runs cooler with more punch. This guide explains what each setting does and how to tune them.
## The Fundamentals: How an ESC Drives a Brushless Motor
A brushless motor has three phases. The ESC energizes them in sequence to create a rotating magnetic field. The rotor (with permanent magnets) chases this field. Three key parameters control the quality of this interaction:
1. **Motor Timing**: When the ESC energizes the next phase relative to the rotor’s position.
2. **Demag Compensation**: How the ESC handles back-EMF spikes that disrupt rotor position sensing.
3. **PWM Frequency**: How fast the ESC switches the MOSFETs on and off to control current.
## Motor Timing Deep Dive
### What Timing Controls
Timing defines how many degrees **before** the rotor aligns with a stator pole the ESC commutates to the next phase. Higher timing fires the next phase earlier — giving the magnetic field a head start.
| Timing Value | Degrees (approx) | Effect | Best For |
| — | — | — | — |
| Low (0-5°) | 0-5° | Coolest running, best efficiency | Cruising, long range |
| Medium (5-15°) | 5-15° | Balanced power and heat | General freestyle |
| Medium-High (15-20°) | 15-20° | More top-end RPM, warmer motors | Aggressive freestyle |
| High (20-25°) | 20-25° | Maximum top-end RPM, hot motors | Racing (short flights) |
| Auto | Variable | ESC self-adjusts based on RPM | Set-and-forget convenience |
### The Heat Tradeoff
Higher timing extracts more RPM and power from the same motor at the cost of efficiency. For every 5 degrees of advance, expect:
– 3-5% more peak RPM
– 5-8% more motor temperature
– 2-4% less flight time
For most 5-inch freestyle pilots, **Medium (15°)** is the sweet spot. Racers who fly 2-minute heats can run **High (20-22°)** because the quad lands before heat becomes a problem.
## Demag Compensation Explained
### What Causes Demagnetization Spikes?
When the ESC commutates, the collapsing magnetic field in the previous phase generates a voltage spike (back-EMF). The ESC senses this back-EMF to determine rotor position — it is how sensorless ESCs work. But at high RPM or under heavy load, these spikes can be so large they confuse the position detection, causing the motor to lose sync.
### Demag Compensation Levels
| Setting | Behavior | When to Use |
| — | — | — |
| Off | No compensation | Low-RPM, light-load flying |
| Low | Mild filtering of BEMF spikes | Most setups — good default |
| High | Aggressive filtering | High-KV motors, heavy props, high timing |
| Auto | ESC adjusts dynamically | Unknown setups, troubleshooting |
**Symptoms of insufficient demag comp**: Motor chirps/screams at full throttle, desyncs during punch-outs, ESC reboots in flight.
**Symptoms of excessive demag comp**: Reduced top-end power (ESC over-filters and misses commutation opportunities), sluggish throttle response.
## PWM Frequency: The Switching Rate
PWM frequency controls how many times per second the ESC MOSFETs switch on and off to regulate current. Higher PWM = smoother motor but more switching losses (heat in the ESC).
| PWM Frequency | MOSFET Switching | Motor Smoothness | ESC Heat | Best For |
| — | — | — | — | — |
| 24 kHz | Low | Adequate | Cool ESC | Most builds (default) |
| 48 kHz | Medium | Very smooth | Slightly warmer | Smooth freestyle, cinematic |
| 96 kHz | High | Buttery smooth | Warm ESC | HD / cinematic rigs with cooling |
### The 48 kHz Revolution
The shift from 24 kHz to 48 kHz PWM (enabled by Bluejay and BLHeli_32) was one of the biggest improvements in FPV motor control. At 48 kHz:
– Motors run **noticeably smoother** with less vibration.
– Throttle resolution feels improved, especially in the low range.
– ESC temperature increases slightly (5-10°C) — typically not an issue with modern FETs.
– Flight time **may increase** slightly due to better part-throttle efficiency.
**Recommendation**: Run 48 kHz PWM on all modern builds. The smoothness improvement is worth the minor thermal cost. Only revert to 24 kHz if your ESC runs above 80°C in normal flight.
## Tuning Workflow
### Step 1: Establish Baseline
Start with Medium timing (15°), Low demag comp, and 48 kHz PWM. Fly a full pack, recording motor temperature with an IR thermometer or telemetry.
### Step 2: Tune Timing
Increase timing one step at a time (Medium → Medium-High → High). After each change, fly aggressively for 2 minutes and measure motor temperature. Stop if motors exceed 70°C at the bell.
### Step 3: Address Desyncs
If you hear motor screeching or experience desyncs at high throttle, increase demag compensation (Low → High). If problems persist, reduce timing slightly.
### Step 4: Finalize PWM
If your ESC runs cool (<60°C) after timing is set, keep 48 kHz. If hot (>75°C), consider dropping to 24 kHz.
## BLHeli_32 vs Bluejay vs AM32 Settings Reference
| Setting | BLHeli_32 | Bluejay | AM32 |
| — | — | — | — |
| Timing | 0-31° | 0-31° | 0-31° |
| Demag Comp | Off/Low/High | Off/Low/High | Off/Low/High |
| PWM Freq | 24/48/96 kHz | 24/48/96 kHz | 24/48/96 kHz |
| Rampup Power | 25-150% | 25-150% | Configurable |
| Motor Direction | 1-Normal, 2-Reversed | Same | Same |
| Configuration Tool | BLHeliSuite32 | ESC Configurator | AM32 Configurator |
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