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Adding a ripple to a DC voltage

Started by Unknown December 5, 2014
Hi all,

I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to build a test bench). The current is about 30A. I was wondering if a transformer in serie with the battery could do the job.

Cheers, H.
On 12/5/2014 2:52 AM, habib.bouaziz@gmail.com wrote:
> Hi all, > > I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to > build a test bench). The current is about 30A. I was wondering if a > transformer in serie with the battery could do the job. > > Cheers, H. >
Yes, it can if it is designed to handle the DC current through the winding. This usually means a core with a magnetic gap.
On Friday, December 5, 2014 3:52:49 AM UTC-5, habib....@gmail.com wrote:
> Hi all, > > I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to build a test bench). The current is about 30A. I was wondering if a transformer in serie with the battery could do the job. > > Cheers, H.
You need to seriously consider dropping out of the profession, you're worthless at electronics and always have been.
On Fri, 5 Dec 2014 00:52:39 -0800 (PST), habib.bouaziz@gmail.com
wrote:

>Hi all, > >I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to build a test bench). The current is about 30A. I was wondering if a transformer in serie with the battery could do the job. > >Cheers, H.
The DC is likely to saturate the transformer core unless the transformer is over-sized. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Not with a bridge rect. Damn, can I explain this without drawing it ?=20

Find a tansformer that only puts out like 3 VAC or so, put a bridge on it w=
ith shitty filtering and just add it to the battery voltage. If they want r=
ipple, which is obviously to be able to tell if a device is vulnerable to r=
ipple, they are not worried about an extra volt. So three volts AC, minus t=
wo junction drops per the bridge rectifier will give you about a volt lefto=
ver.=20

Problem is finding the right transformer. With such a stepp voltage and thu=
s impedance ratio, it is not a hard transformer to design and have the curr=
ent level required. The PROBLEM is there is about no market for such transf=
ormer so as such it might be very hard to find one.=20

Try Digikey's selector thingie, who knows if they have one. Just because I =
can't think of an application for the thing doesn't mean there isn't one. h=
owever I would be interestied in where this particular demand might be othe=
r than in this case right here, which is a bit unusual. The whole world is =
trying to get rid of ripple and here we are...
On Friday, December 5, 2014 3:52:49 AM UTC-5, habib....@gmail.com wrote:
> Hi all, > > I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to build a test bench). The current is about 30A. I was wondering if a transformer in serie with the battery could do the job. > > Cheers, H.
So ~ a one ohm load? What frequency? Could you just couple it in with a capacitor? Or a diode? George H.
Le vendredi 5 d=E9cembre 2014 11:50:51 UTC+1, John S a =E9crit=A0:
> On 12/5/2014 2:52 AM, habib.bouaziz@gmail.com wrote: > > Hi all, > > > > I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to > > build a test bench). The current is about 30A. I was wondering if a > > transformer in serie with the battery could do the job. > > > > Cheers, H. > > >=20 > Yes, it can if it is designed to handle the DC current through the > winding. This usually means a core with a magnetic gap.
Ah yes with an air gap magnetic core in order to avoid saturation. Good ide= a. I have simulating this configuration with femm.info. Habib.
Le vendredi 5 d=E9cembre 2014 14:42:35 UTC+1, bloggs.fred...@gmail.com a =
=E9crit=A0:
> On Friday, December 5, 2014 3:52:49 AM UTC-5, habib....@gmail.com wrote: > > Hi all, > >=20 > > I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to bu=
ild a test bench). The current is about 30A. I was wondering if a transform= er in serie with the battery could do the job.
> >=20 > > Cheers, H. >=20 > You need to seriously consider dropping out of the profession, you're wor=
thless at electronics and always have been. ok i will, but you have not appreciate my joke "tchou tchou" about your inc= ompetence on the design of a the high voltage indicator. Habib.
On Fri, 05 Dec 2014 01:52:39 -0700, <habib.bouaziz@gmail.com> wrote:

> Hi all, > > I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to > build a test bench). The current is about 30A. I was wondering if a > transformer in serie with the battery could do the job. > > Cheers, H.
At Test Labs, or to make a local setup, we used tostick a 500VA transformer in series, One of those 'fliament transformers, or for doing a 'sweep' a difficult to find now "Power Audio" matching transformer, tube to speaker step down. I think they'll take the DC current bias. And if you must use two. PS: put in series with the GND of the system so you can easily read the amount of ripple you're injecting.
In article <d44bfb1c-422c-455c-886d-bb392f273ab4@googlegroups.com>,
 habib.bouaziz@gmail.com wrote:

> Hi all, > > I have to add a ripple voltage (1Vrms) in serie to a 24V Battery (to build a > test bench). The current is about 30A. I was wondering if a transformer in > serie with the battery could do the job.
H.- As noted, 30 Amps DC is likely to saturate a transformer. If you can solve that problem, it should work. Use a "variac" to provide an adjustable voltage to the transformer primary. Why not use a regulated power supply instead? It would be easier to modulate a linear voltage regulator to provide ripple. Modulation could be provided either by a signal generator, or by a transformer fed from the mains. Fred