Is it ok to wire a wind turbine like this or what am I doing?

[shamooooot]

hello

I have a wind turbine that I need to measure the speed of, and the wonderful forum members suggested that I measure the frequency between two of the phases and then I can relate it to the speed of the generator.

I got some frequency meters and they couldn't pick the frequency due to which I assume to be low voltage. Then I connected these two phases to a step up transformer and the frequency meter now reading the frequency of the signal.

However I am concerned about this connection as it's shortening these two phases through the transformer and I need help.

[Benta]

If the transformer primary is rated for the same voltage as the maximum generator phase-phase voltage, then it's fine.

[uer166]

Since frequency is variable, the transformer presents a variable impedance to the turbine generator depending on the RPM. At low RPM it's basically a dead short circuit that may cause the turbine to struggle to start up.

Whether it's an issue or not I don't know, but it might be a good idea to add some extra impedance (i.e. a resistor) in the transformer primary to at least limit the current.

[Benta]

Yeah, my answer was too simplistic, but with zero information about the generator it's impossible to be specific.
A "How to ask a question" sticky post might be an idea. OTOH, there's already the "NEWBIES PLEASE READ BEFORE POSTING", but no one reads that.
Oh well...

[shamooooot]

Hello

The generator is Three-phase AC permanent magnet synchronous generator.

[DTJ]

Capacitively couple your freq meter.

or

Use an inductive pickup and a small magnet (two for balance) on the rotor.

[wofritz]

I used an optocoupler with series resistor and antiparallel diode for galvanic isolation. This worked quite well on a wind turbine in a 12V solar/wind system in a range 10 to more than 1000 RPM. Disadvantage: Needs a power source and maybe additional pulse forming depending on your counter (I used an Arduino for frequency measurement)
 

[Doctorandus_P]

I don't like adding shunt resistors to high current or voltage cables. They reduce efficiency and can be a maintenance issue (moisture, dirt). There are various ways in which you can add a HALL sensor to your cable to remotely sense the magnetic field. You can also get current clamps that just clamp around the existing cable, and both methods can be used to sense the frequency. (And the current) At very low RPM these sensors may have not enough output to sense reliably. If that is an issue, then using some sensor to directly measure rotor rotations is probably a better option.