Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 00:31 15 Jul 2025 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Windmills : measuring rpm with hertz

Author Message
Ben
Newbie

Joined: 10/08/2007
Location: Australia
Posts: 18
Posted: 11:40am 11 Jun 2008
Copy link to clipboard 
Print this post

Hi ben here .I have a f&p 80 series wired 3 phase 7 groups of 2 pole star as on site.I got a hertz meter and it reads about 300 hz .Does this mean 300 rpm.On another note I get vibration at high rpm.I have balanced my 2.4m blades on axis and horizontaly as posted on site.I made the blades from timber and have blade angels as close as possible,have I missed something.
 
Gill

Senior Member

Joined: 11/11/2006
Location: Australia
Posts: 669
Posted: 12:12pm 11 Jun 2008
Copy link to clipboard 
Print this post

G'day Ben,
To your first question, No.
Seems you missed Bruce's post of a few days ago asking for the same info on Hz conversion to RPM. Here is the info again.

I'm guessing you have read all the related articles saying:

tip to tip measurements must be same.
static balance must be right.
dynamic balance too if possible to test/adjust.
pitch must be same on each blade.
aerodynamic profile must be same.
blade tracking must be same.
surface finish must be same.
rum must be served in a clean glass.
bearings and physical mounting must be up to scratch.


That just about covers it. You must be out on one or more of them. Which do you reckon?
was working fine... til the smoke got out.
Cheers Gill _Cairns, FNQ
 
Ben
Newbie

Joined: 10/08/2007
Location: Australia
Posts: 18
Posted: 11:17am 12 Jun 2008
Copy link to clipboard 
Print this post

Thank you gill I did not look at bruces e-mail .My mill is doing over 600rpm regulary .I supose it is fair enough it shakes a bit.
 
imsmooth

Senior Member

Joined: 07/02/2008
Location: United States
Posts: 214
Posted: 06:31pm 12 Jun 2008
Copy link to clipboard 
Print this post

I was able to accurately measure RPM with a digit multimeter HZ setting. I connected the leads to two of the three phase output leads. For a 56 magnet (28 pole) rotor 28 hz is one rotation/sec which is 60 rpm. I verified this by using a strobe counter simultaneously with the multimeter. You will need to adjust the HZ:rpm ratio if the number of poles are different.
 
Print this page


To reply to this topic, you need to log in.

The Back Shed's forum code is written, and hosted, in Australia.
© JAQ Software 2025