Description

WE ARE RICH ELECTRONICS

WE PURCHASE SURPLUS

ELECTRONIC COMPONENTS

AND EQUIPMENT!

For sale here we have the following parts…

Choose from 1, 2, 4 or 10 Pieces select quantity required from drop down box above.

The larger the quantity the greater the discount!

BHC Aluminium Electrolytic Capacitor

The BHC ALT20A 153DD 025 is a high-grade 15,000µF, 25Vdc solder-tag electrolytic capacitor, often used for audio and industrial power applications. Key features include a 40mm x 55mm size, 26,000-hour life expectancy, and low ESR

15000uF 25Vdc Capacitor

Tolerance: -10 +30%

Solder Terminals

Can Diameter 40mm

Can Length 55mm

Life Expectancy 26000 hours

This range of long life high grade capacitors,
features low e.s.r., high ripple current
ratings and outstandingly good high frequency
impedance.

ALT styles are designed for flying lead connection

Ripple current
The following values are approximate only, to give an
indication of the effects of frequency and
temperature on ripple current. More accurate data
can be obtained by referring to the Application Notes
available from BHC Aerovox.

FREQUENCY CORRECTION
Capacitors shall withstand the rated r.m.s. ripple
current as given in the tables at upper category
temperature in circulating air. For frequencies other
than those shown the following multipliers should be
applied to the 100Hz ripple current.
RATED FREQUENCY (Hz)
VOLTAGE d.c. 50 100 500 1k >10k
0 – 25 0.89 1.0 1.05 1.06 1.07
40 – 160 0.81 1.0 1.28 1.33 1.39
200 – 450 0.75 1.0 1.54 1.70 1.89

For datasheet search…BHC ALT20A 153DD 025

Or go directly to…

http://www.audio-talk.co.uk/archive/bhccat.pdf

Extract from the data sheet:

Shelf Life
The capacitance, ESR and impedance of a capacitor
will not change significantly after extended storage
periods, however the leakage current will very slowly
increase. BHC Aerovox products are particularly stable
and allow a shelf life in excess of ten years at room
temperature.
If the measured value is higher than twice the specified limit
then re-ageing is recommended.

These are marked 9524 which we believe is the date code.

Re-age Procedure
Apply the rated voltage to the capacitor at room
temperature for a period of one hour, or until the
leakage current has fallen to a steady value below the
specified limit. During re-ageing a maximum charging
current of twice the specified leakage current or 5mA
(whichever is greater) is suggested.

Please be aware these are electrolytic capacitors and by their very nature require a high degree of skill when handling and installing, they are intended for use by qualified electronic engineers, please do not purchase and engage in any of these procedures if you are not competent to do so!

Reforming Electrolytic Capacitors

• Manufacturers claim that most old electrolytics can be saved if the correct procedure is followed, regardless of how long they have been unused. Such capacitors must be “reformed”. This process consists of applying rated voltage through a resistance (about 30,000 ohms, five watt) for five minutes plus one minute for each month of storage (see figure 6). As the capacitor reforms, the voltage across the resistor will drop (measured at the Xs in Figure 6). If that voltage will not drop below 10% of applied voltage after one hour, the capacitor is probably beyond help.Reforming Electrolytic Capacitors – The process of reforming an old aluminum electrolytic capacitor consists of the application of rated voltage, through a resistor, for a period equal to five minutes plus one minute per month of storage.The electrolytics appearing on the surplus market have often been in storage for a very long period indeed. Some manufacturers use a visible code, of which the first two digits indicate the year of manufacture.The circuit shown in the sketch above works reasonably well. Apply the rated voltage through a 5W resistor. Anything from 20K-50K will do, as this is far from a precision process. The meter is used to measure the voltage drop across the resistor; when no current is flowing, there will be no drop. Obviously, when there is a large voltage drop (more than 20% of the applied voltage), there must be a significant current flow through the capacitor. The nature of a proper capacitor is to impede DC current flow, so when there is such flow, something must be wrong.Note: Apply the appropriate D.C. voltage to the capacitor with a D.C. power supply. An old Kepco, Lamba etc. tube regulated lab power supply rig works great. Be sure to observe the proper polarity!

PLEASE NOTE!

These parts came to us as part of a lot of surplus stock from a large ‘Mispec’ type Co. and have been kept in storage for some time, we have therefore classified them as ‘new other’, they are however in good serviceable condition, thogh they may need reforming, the photographs are representative of their general condition, being of one of our actual stock, and, as with all our products they come with a full guarantee.