What kind of diodes should I buy?

[theiceman]

Hello guys how are you. First of all thank you for taking the time to answer newbies questions, God bless you. Suppose I have a machine I will use to charge a 12V Battery bank, I would like to know what I need to build the rectifier, I mean if I need Diodes I would to know the specifications I have to ask for at the store. Thank you very much.

Luis.

[TomW]

Luis;

A lot depends on the turbine itself. voltage and current expected are critical bits of information for this.

For a common home built here you will need a bridge rectifier probably a couple. These are prewired diodes to full wave rectify the AC into DC.

I think we will need more information on your plan.

I like to size them rated at at least 2X expected voltage and current.

Tom

[theiceman]

Dear Tom. We are just starting out a project, and I am in charge of purchasing stuff and I have to do it in advance, and they told me they are going to try to copy this turbine:

http://www.otherpower.com/turbineplans.html

Could you help me out leting me know what kind of bridge rectifiers do I need to purchase for this particular model.

Thank you.

Luis

[kurt]

http://otherpower.com/rectifier.html

this sight sells the recommended bridges here.

http://www.forcefieldmagnets.com/catalog/product_info.php?cPath=22_30&products_id=98

mite wanna read the instructions on that page a bit better before you go buying stuff..... it says right in the instructions 3 bridges min 35 amps.

you could also get a 3 phase bridge off of ebay but that would be deviating from the instructions

[theiceman]

THANK YOU!

[la7qz]

Hi

These are the bridges I use in my turbine. I use three of them, using two inputs from each and have installed them in a box with big heat sinks (an automatic fan is being added now). Originally, the alternator had two of these rectifiers and used both inputs of one and one input of the other. However, since I have seen a maximum of 34.95 Amps at peak according to my Doc Wattson meter (at 1170 rpm), using three rectifiers and doubling the inputs seems safer.

While I'm here, I have a question. At the moment I am using one rectifier for each phase. Would it be safer to "stagger" the outputs from the turbine? I mean connect phase A to one input of rectifier 1 and one input of rectifier 2, phase B to rectifier 2 and 3 and phase C to rectifier 3 and 1? I'm thinking that would reduce the peaks through each rectifier, but maybe it wouldn't matter much since the same amount of current would be flowing and the same amount of heat generated.

Owen

[MAXial dreamer]

not sure what your measuring.  If thats your total output I think your ok.

[wooferhound]

NO ,  don't do it

It will not have any affect on peak distribution. as the drawing shows, each phase is going through its own rectifier, this distributes the peaks perfectly evenly.

[David Hosegood]

HI THIS WILL SOLVE YOUR PROBLEM ITS AN OFF THE SHELF PRODUCT ITS VERY ROBUST AND IT WORKS WELL FOR F@P VERTICAL WIND TURBINE ITS BEEN IN OPERATION FOR SOME TWO YEARS NOW

YOU WILL NEED SOME FORM OF BATTERY MONITORING IF YOU DO USE THIS JUST ON ITS OWN THOUGH

CHEERS DAVE

VUO 36 VUO 36

Three Phase Rectifier Bridge

IdAV = 35A

VRRM = 800-1800 V

VRSM VRRM Type

+

VDSM VDRM

VV

~

~

800 900 VUO 36-08NO8

~

1200. 1300 VUO 36-12NO8
      
1400. 1500 VUO 36-14NO8
      
1600. 1700 VUO 36-16NO8 1800
      
1900. VUO 36-18NO8
      
      

Features

Symbol Conditions

Maximum Ratings

+

-

~

~

IdAV

IdAVM

TC = 85°C, module

TC = 62°C, module

27. 
    
35. 
    
    

A

A

IFSM TVJ = 45°C;

VR = 0

t = 0 ms

t = 8.3 ms

(50 Hz)

(60 Hz)

550. 
     
600. 
     
     

A

A

TVJ = TVJM;

VR = 0

t = 0 ms

t = 8.3 ms

(50 Hz)

(60 Hz)

500. 
     
550. 
     
     

A

A

I2t TVJ = 45°C;

VR = 0

t = 0 ms

t = 8.3 ms

(50 Hz)

(60 Hz)

520. 
     
520. 
     
     

A2s

A2s

TVJ = TVJM;

VR = 0

t = 0 ms

t = 8.3 ms

(50 Hz)

(60 Hz)

250. 
     
250. 
     
     

A2s

A2s

TVJ

TVJM

Tstg

-40...+ 50

50

-40...+ 50

°C

°C

°C

VISOL 50/60 Hz, RMS

IISOL < mA

t = min

t = s

2500. 
      
3000. 
      
      

V~

V~

Md Mounting torque (M5)

( 0-32 UNF)

2. ± 0%
   
8. ± 0%
   
   

Nm

lb.in.

• Package with ¼" fast-on terminals
  
• Isolation voltage 3000 V~
  
• Planar passivated chips
  
• Blocking voltage up to 800 V
  
• Low forward voltage drop
  
• UL registered E 72873
  
  

Applications

• Supplies for DC power equipment
  
• Input rectifiers for PWM inverter
  
• Battery DC power supplies
  
• Field supply for DC motors
  
  

Advantages

• Easy to mount with one screw
  
• Space and weight savings
  
• Improved temperature & power cycling
  
  

Dimensions in mm (1 mm = 0.0394")

Weight Typ.

22 g

Symbol Conditions

Characteristic Values

IR VR = VRRM TVJ = 25°C 0.3 mA

TVJ = TVJM 2.0 mA

VF IF = 50 A TVJ = 25°C

.7 V

VT0 For power-loss calculations only 0.8 V

rt 7.4 mW

6. 3 x 0.8
   
22. 1 ±0.5
    
10. ±0.2
    
    

RthJC per diode; 20° el. 7.50 K/W

per module .25K/W

RthCH per diode; 20° el. 8.40 K/W

per module .40 K/W

dS Creeping distance on surface 2.7 mm

dA Creepage distance in air 9.4 mm

a Max. allowable acceleration 50 m/s2

ABCDE28.5 ±0.28 ±0.312 ±0.3

28. 5 ±0.2
    
12. ±0.3
    
    

Data according to IEC 60747 and refer to a single diode unless otherwise stated.

IXYS reserves the right to change limits, test conditions and dimensions. 20070807

© IXYS All rights reserved - 2

VUO 36 VUO 36

Fig. Forward current versus Fig. 2 Surge overload current per diode Fig. 3 I2t versus time ( - 0 ms)

voltage drop per diode IFSM: Crest value. t: duration per diode

Fig. 4 Power dissipation versus direct output current and ambient temperature Fig. 5

Maximum forward current at

case temperature

Constants for ZthJC calculation:

Fig. 6 Transient thermal impedance per diode

i Rthi (K/W) ti (s)

0. 94 0.024
   
2. 0.556 0.07
   
3. 2.25 5.8
   
4. 6.3 8.5
   
   

Constants for ZthJK calculation:

i Rthi (K/W) ti (s)

0. 94 0.024
   
2. 0.556 0.07
   
3. 2.25 5.8
   
4. 6.3 8.5
   
5. 0.9 28
   
   

IXYS reserves the right to change limits, test conditions and dimensions.

© IXYS All rights reserved

2 - 2

[TomW]

There is a CAPSLOCK key somewhere on your keyboard. Please use it to turn OFF the CAPS before posting again.

Might help to actually include a source for the parts in a post referencing them as a solution?

Tom

[rpcancun]

These are the diodes I am using, there are no electronic suppliers here

that I can find, these where bought from an auto parts store, theyre supposed to be 35a diodes, I then mounted them to a cpu heat sink (2 per sink 1/2 inch hole for each diode)...can anyone tell me more about them?

(the guys at the counter didn't have any other info)

Thx

Rob

[Ungrounded Lightning Rod]

When paralleling multiple diodes to increase current capacity you want the diodes to match as closely as possible.  Their voltage/current curve is very non-linear (in particular: it's an exponential) so a very small mismatch throws most of the current into one of the diodes.

So you want them:

 - To be at the same temperature.

 - To be from the same batch of diodes to minimize process variations.

 - To have equal wiring resistance.

Using both sets of diodes in a bridge (thus probably from the same lot or even on a common chip, certainly on a common heatsink, which tends to equalize the temperature) for ONE phase and soldering the incoming AC line for that phase to the midpoint of a wire running between the two AC terminals of that bridge (to provide a tiny and equal series resistance) tends to do this.  Splitting the phases between two different bridges specifically AVOIDS doing this (and tempts you to use different wire lengths, further {and drastically} increasing the imbalance.)