The case of the overheating Blower

Reply

  #1  
Old 12-16-14, 08:46 PM
Member
Thread Starter
Join Date: Dec 2014
Location: philippines
Posts: 4
Received 0 Votes on 0 Posts
Question The case of the overheating Blower

I recently installed a blower pump to supply air to a newly constructed aerobic septic system . the pump itself is of the linear piston design, there are no moving parts other than the piston itself. A diode is wired in series with the inlet power supply thereby creating a half wave rectifier, this is what alternately drives the spring loaded pistons, it's a simple setup. The pump itself runs on 120 volts a/c , the voltage supply at this location is approx. 230 volts a/c. the pump itself draws about 100 watts. I have installed a 2.5 kw step down transformer with built in voltage regulation. this pump is designed to run continuously. The pump starts fine , but after about 30 - 45 minutes it will shut down due to high heat ( built in thermal switch ), after cooling down it will restart. So far I have done the following: checked the air filter in the pump ( it's clean ,no dust or debris ) checked output voltage of the transformer , reads approx. 115va/c .The pump itself is putting out designed pressure ( approx. 2p.s.i. )the pump is a Medo La 100. Anyone have any suggestions why this continuous overheating problem ?
 
Sponsored Links
  #2  
Old 12-16-14, 11:08 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 53,186
Received 376 Votes on 353 Posts
Welcome to the forums.

A diode is wired in series with the inlet power supply thereby creating a half wave rectifier, this is what alternately drives the spring loaded pistons
Are you completely sure of that ???

A diode would remove one half of the AC sine wave and the resulting voltage to the motor would be a type of DC and half the voltage. I went thru all the parts lists and installation instructions and found no mention of any diode.

My opinion.... the diode should not be there.
 
  #3  
Old 12-17-14, 07:25 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Location: USA
Posts: 4,029
Received 18 Votes on 18 Posts
Hi, seeing you are Non-US ,are you connected with the right frequency ie. 50 or 60 Hz.it seems like that diode might have something to do with the electro magnet that drives the piston.
Just a thought.
Geo
 
  #4  
Old 12-17-14, 12:53 PM
Member
Thread Starter
Join Date: Dec 2014
Location: philippines
Posts: 4
Received 0 Votes on 0 Posts
If you go on their website (MEDO.COM ) Pull up the LA series blowers ( mine is a 100 ) you'll find a link explaining how the pump works.Basically each piston is attached to a electromagnet which becomes energized by the pulse created by the diode and then becomes de-energized , this alternating action is what causes air pressure at the pump outlet. this isn't an inductive motor with a stator and rotor .
 
  #5  
Old 12-17-14, 01:03 PM
Member
Thread Starter
Join Date: Dec 2014
Location: philippines
Posts: 4
Received 0 Votes on 0 Posts
Yep i thought the problem maybe frequency drift, bdway the power supply is 220v a/c 60 hz . but this pump isn't inductive ( no windings to overheat ) so a frequency change wouldn't affect it , only difference frequency drift would do would be cause the pump to run slower...
 
  #6  
Old 12-17-14, 06:59 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 53,186
Received 376 Votes on 353 Posts
A silicon diode between the coils converts the full-wave input current into half-rectified
current. The result is a resonant spring-mass assembly, energized by a pulsating magnetic field
I finally found this little blurp.
Best thing I can recommend is check directly with the company.
 
  #7  
Old 12-17-14, 08:35 PM
Member
Thread Starter
Join Date: Dec 2014
Location: philippines
Posts: 4
Received 0 Votes on 0 Posts
Yes that's what I was explaining re operation of this pump ...and yes I've spent about an hour on the phone with the company already, with know apparent solution. The pump is brand new , no discernible defects , and most of all it's putting out the ideal pressure , according to the performance curve data.at this point I can only think it has something to do with step down Transformer...overheating to the point of tripping the thermal switch, is usually a sign of excessive current...rapid switching of diodes in variable speed motors has been known to cause harmonic distortion up line from the motor itself....is this what is happening here?....is it the transformer windings that are being affected ? and so causing a distorted sine wave , leading to this overload condition?...if the pump itself were overloaded it would show up as a reduced operating pressure..
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: