The no-load V/f should be constant and the max load power should be at 50% max RPM.

But I recall they rate max at power 60 Hz.

What is the [psi / watt] at 33 Hz.

The prime mover is pressurized air (150 psi - 190 psi). The generator is a 240 v 60hz 10 amp motor (wanco AB20L) The load below is a test load 120v 500 watt heater.

The real load will be a bank of 12 volt batteries wired to be 24 volt. I am struggling to understand why the frequency/rpm remains the exact same even though the prime mover is increasing.

With load:

150 psi / 55 volts / 0.9 amps / 33 Hz

170 psi / 78 volts / 2.1 amps / 33 Hz

190 psi / 112 volts / 4.1 amps / 33 Hz

Without load:

150 psi / 85 volts / 37 Hz

170 psi / 168 volts / 47 Hz

190 psi / 235 volts / 59 Hz

| | | | | | Pwr Max= | 2400 |

PSI | V [volts] | I [Amps] | f [Hz] | psi/VA | f / fo | Pwr [W] | P / Pmax |

150 | 55 | 0.9 | 33 | 3.03 | 89% | 49.5 | 2.1% |

170 | 78 | 2.1 | 33 | 1.04 | 70% | 163.8 | 6.8% |

190 | 112 | 4.1 | 33 | 0.41 | 56% | 459.2 | 19.1% |

| | | | | | | |

PSI | V [volts] | no load | fo (Hz) | V / f | | | |

150 | 85 | “0” | 37 | 2.30 | | | |

170 | 168 | “0” | 47 | 3.57 | | | |

190 | 235 | “0” | 59 | 3.98 | | | |

Conclusion not enough Prime Mover source power to generate 2400 VA out at 190 psi. perhaps suboptimal torque conversion 1:1 and needs pulleys. Or better use a field regulated Alternator.