23 April 2011

Trident Powercraft - TAVR 20

Trident Powercraft Pvt Limited (TPPL) is a Bangalore based company manufacturing AC Generators (Alternators), DC Motors and Wind Generators. They have two manufacturing units one at Bangalore and the second at Hubly both in Karnataka. Main customer of TPPL is Kirloskar Oil Engines Limited (KOEL). Most of the Kirloskar Green DG sets available are manufactured with KOEL engines and TPPL Alternators. TPPL also do business with Ashok Leyland Limited and Mahindra Powerol In 2009 Emerson acquired TPPL for Leroy Somer Power Generation.

Here I am sharing some informations regarding TAVR 20 used in alternators under 125kVA manufactured by TPPL. TAVR 20 has 6 terminals. This AVR can be used in both single phase and three phase alternators. When used in a single phase alternator short the terminals  N & N1 of AVR. Then connect output phase to U and output neutral to N of AVR. Also connect F1 and F2 leads from the exciter field to the respective terminals of AVR. There will be no connection at V terminal of  AVR. When used in a three phase alternator there is no need to short N and N1 terminals of AVR. Connect output phase U, V and neutral N to the U V and N terminals of AVR and also connect F1 & F2 leads from exciter field to the F1 and F2 terminals of AVR. There will not be any connection at N1 terminal of AVR.

This AVR has three indicating LEDs (clear type, when they glow RED) and they are.
  1. UF (Shows Under Frequency, indicating low speed of prime mover) 
  2. OE - Over Excitation (The excitation voltage/current drawn by alternator is more than maximum value) 
  3. SL - Sensing Lead open (Sensing lead U-V is open circuited). 
AVR also have a F6A, 240V 20mm Glass fuse for protection. There are multy turn POT resistances
  1. OE - To set Excitation Limit 
  2. UF - To set Under frequency cut off 
  3. S - To set the voltage stability 
  4. V - To set the output Voltage. 
All POTs except V are factory set and sealed. They need not be disturbed at site. We can adjust the output voltage by turning the multy turn POT V.  All TPPL alternators are fixed with two permanent magnets (PMGs) on Exciter Field core. So there will not be any voltage built-up failure complaints due to loss of residual magnetism. The normal residual voltage is in between 30 to 40V (between two phases). The following figure shown connection details of TAVR 20.


  1. hello sir,
    we are facing a problem of reduced voltage from 415V to 386V of 750 KVA TRIDENT generator with excitation voltage of 55V dc.So sir please help me out how to increase the output voltage to 415V its very urgent.

  2. Please operate the DG at no-load. check the excitation voltage at F1F2 (DC) terminals. Compare it with the test certificate. If it is high there may be some fault with the windings / diode/ varistor. If the voltage is getting reduced on load then also check the voltage at F1F2 if it is more than 55V then also we can suspect any internal fault.

  3. What is the cost of this product

  4. yeah i agree so nice,
    i recommand it to my friends and i,ll be back again and again visit dies and mould manufacturers in india for more info.

  5. nice article.....sir.

    pankaj kumar

  6. Sir, my 15 Kva generater KOEL giving 0 volt in all three phases. TAVR 10 regulater used. When I start gender at F1 & F2 there is no voltage. When gives 12 volt dc externali at F1(+) F2(-) output raise to 27 v at phase and neutral. Pl guide me for rectification.

    1. Dear Anuj Thank you for visiting my blog. Normally KOEL DG Set with Trident / Nidec / LeroySomer Alternator will develop a balance output voltage of about 40V (between phase) it the diodes and winding are healthy. If you are getting zero volt output complaint will be either with diodes or with windings. There are four windings in KOEL alternator exciter field, exciter armature, main field and main stator. If main stator winding is faulty the the output voltage will be unbalanced. If you are getting a balanced 27V output with 12V external supply applied to F1F2 leads (ie exciter field) then stator winding may not have any complaint. Fault may be with diodes, varistor or any other winding.

  7. TAVR 20 is discontinued now. The new AVR with better performance is R120 for three phase alternator and R121 for Single Phase Alternators. We can use R120 for single phase alternators with interlinking N&N1 terminals and connecting input supply at U & N Teminals. No connection at Terminal V.

  8. Great and really helpful article! Adding to the conversation, providing more information, or expressing a new point of view...Nice information and updates. Really i like it and everyday am visiting your site..
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