question on fuses

Antonix · 12th October 2005, 01:37 AM

I have maked an upgrade on my Carver TFM 15 by change the power supply capacitors.

The original are 2 x 15000uF and i have climbed on 4 x 10000uF.

I have changed also the rectifier bridge with a kpfc-35 35A.

Naturally the old fuses of 6,3A are fired and i must cange this with a bigger fuses.

How can i calculate the values ?

Can i use a current limiter ? What ?

EchoWars · 12th October 2005, 02:04 AM

Quote:

Naturally the old fuses of 6,3A are fired and i must cange this with a bigger fuses.

Nothing natural about it...sounds like a problem to me.

anatech · 12th October 2005, 02:23 AM

Hi Antonix,
I'm not sure if you added these and kept the originals, or just replaced the originals. Leave the original values in. This is not a normal power supply at all!

Return it to original and see if it still blows fuses. It might be broken now.

-Chris

Antonix · 12th October 2005, 01:10 PM

Thanks for your suggestions.

I have "only" inverted the polarity of one capacitor.

Now all work great with a 6A fuse.

anatech · 12th October 2005, 01:19 PM

Hi Antonix,
That is great news.

Please be aware that this is a triac regulated power supply. The internal voltages are regulated by changing the phase that the AC triac fires at. The transformer is different as well.

-Chris

Antonix · 12th October 2005, 02:28 PM

Sorry for my english anatech
but i don't understand what you want to say.

anatech · 12th October 2005, 02:43 PM

What I am trying to say is: your Carver is not a "standard" unit. You have to be very careful working with the power supply and transformer. They do not work in a normal way. Some "tweeks" may cause you to damage to your Carver. The modifications may not do what you think they will do.

Likewise, the amplifiers are not normal. Try not to work on them unless you understand how the circuit works.

-Chris

Antonix · 13th October 2005, 02:30 PM

Thanks for your suggestion, I understand you now.

I have a lot of experience on electronics by many year and I understand how the circuit works.

What I am trying to say is that the power supply of my Carver TFM 15 is the simplest power supply : there are only one bridge and 2 capacitors and never triac or other transistor to regulate voltage.

I have changed the old capacitors also because they were inflated and I have reveal why.

The old capacitor were 50V and with my surprise I have measured that the voltage DC out are +-52V.

Now I have mounted 63V capacitors.

If you want I can post you a foto.

anatech · 13th October 2005, 02:52 PM

Hi Antonix,
You're right! I thought the TFM-6C was the only standard supply. As it turns out, so is the TFM-15. We didn't have any trouble with these so I never really got into this one.

As far as your supply voltages are concerned, they are supposed to be 52 VDC. The supply caps are in fact spec'd at 50V. Someone deserves a slap upside the head, 63V caps were the proper ones. That goes to show you what relying on the safety factor will get you.

Antonix, thanks for pointing that out. I'll make a note of this.

-Chris

12th October 2005, 01:37 AM	#1
Antonix diyAudio Member Join Date: Apr 2005 Location: BA	question on fuses I have maked an upgrade on my Carver TFM 15 by change the power supply capacitors. The original are 2 x 15000uF and i have climbed on 4 x 10000uF. I have changed also the rectifier bridge with a kpfc-35 35A. Naturally the old fuses of 6,3A are fired and i must cange this with a bigger fuses. How can i calculate the values ? Can i use a current limiter ? What ?

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12th October 2005, 02:23 AM	#3
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Antonix, I'm not sure if you added these and kept the originals, or just replaced the originals. Leave the original values in. This is not a normal power supply at all! Return it to original and see if it still blows fuses. It might be broken now. -Chris

12th October 2005, 01:10 PM	#4
Antonix diyAudio Member Join Date: Apr 2005 Location: BA	Thanks for your suggestions. I have "only" inverted the polarity of one capacitor. Now all work great with a 6A fuse.

12th October 2005, 01:19 PM	#5
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Antonix, That is great news. Please be aware that this is a triac regulated power supply. The internal voltages are regulated by changing the phase that the AC triac fires at. The transformer is different as well. -Chris

12th October 2005, 02:28 PM	#6
Antonix diyAudio Member Join Date: Apr 2005 Location: BA	Sorry for my english anatech but i don't understand what you want to say.

12th October 2005, 02:43 PM	#7
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	What I am trying to say is: your Carver is not a "standard" unit. You have to be very careful working with the power supply and transformer. They do not work in a normal way. Some "tweeks" may cause you to damage to your Carver. The modifications may not do what you think they will do. Likewise, the amplifiers are not normal. Try not to work on them unless you understand how the circuit works. -Chris

13th October 2005, 02:30 PM	#8
Antonix diyAudio Member Join Date: Apr 2005 Location: BA	Thanks for your suggestion, I understand you now. I have a lot of experience on electronics by many year and I understand how the circuit works. What I am trying to say is that the power supply of my Carver TFM 15 is the simplest power supply : there are only one bridge and 2 capacitors and never triac or other transistor to regulate voltage. I have changed the old capacitors also because they were inflated and I have reveal why. The old capacitor were 50V and with my surprise I have measured that the voltage DC out are +-52V. Now I have mounted 63V capacitors. If you want I can post you a foto.

13th October 2005, 02:52 PM	#9
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Antonix, You're right! I thought the TFM-6C was the only standard supply. As it turns out, so is the TFM-15. We didn't have any trouble with these so I never really got into this one. As far as your supply voltages are concerned, they are supposed to be 52 VDC. The supply caps are in fact spec'd at 50V. Someone deserves a slap upside the head, 63V caps were the proper ones. That goes to show you what relying on the safety factor will get you. Antonix, thanks for pointing that out. I'll make a note of this. -Chris

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