Description: Vintage radio power transformer. Features: - High voltage: 300-0-300 35MA - Secondary Power Supply: 3.15-0-3.15 1.9A - Voltage: 0-4-5-6.3 1.5A - Number of Valves: 4 - Primary: 230V - Power: 45VA - Measurements: Length 7.5cm x Height 6.2cm x Width 8cm - Weight: 1,420Kg - Distance between holes: horizontal position: 6.2 x 5 cm, vertical position: 5 x 6.3 cm Made in Spain, high quality copper. The price is per unit. We have more transformers of different capacities. For more information, see photograph. Ref. 25-17028 POWER TRANSFORMER FOR RADIOS, AMPLIFIERS, INSTRUMENTS, SOURCES, ETC. DESIGNED WITH VALVES The fastening system consists of two equal frames that evenly press the core preventing any type of noise produced by vibration. In the horizontal position, you get a wide base and a low point of gravity that allows mounting in places of limited height The upright position is frequently used in older radios, primarily across all PHILIPS brand ranges and the like. Slots in the frames allow you to attach some components, valve sockets, voltage changes, etc. that some manufacturers used to mount. By disassembling the corresponding frame on the side of the connections, the transformer can be mounted in the trans-chassis position, also common in many radio and amplifier assemblies, especially those from mounting kits. This type of assembly requires a longer length of the screws that are supplied. Once mounted, the frame can be dispensed with for better access to the connections, or retained for greater consistency in fastening. POWER TRANSFORMERS FOR THERMIONIC VALVE APPLIANCES. The power transformer is responsible for converting the voltage of the mains applied to the transformer primary, into the different voltages required in the secondary circuits. For this reason, under current regulations, 4000v insulation between the two must be guaranteed. The input jack should be protected by a fuse that supports the total power consumed by the computer. E.g. The 17031 model has a power of 65va. Applying Ohm's law results in a full load current of: 65va /230v = 0.28A. Increasing this margin by 12%, the fuse in question for a normalized current value will be 315mA-L (slow melting) The voltages supplied by the transformer are expressed in alternating current, AC (Alternating Current) and must be converted to direct current, DC (Direct Current) to power the different sections of the receiver or amplifier equipment. This function is handled by the rectifier circuit, and it can incorporate a valve or semiconductor diodes. The transformers presented here incorporate a separate winding for filament heating of the grinding valve with 4, 5, and 6.3 V outlets. These voltages cover most existing grinding valves. The AZ41 is heated to 4v, the GZ34 to 5v, and the EZ81 to 6.3v as an example of three very common grinding valves in radios and amplifiers. The winding described for heating the grinding valve under no circumstances should it be used to feed other elements as it is connected to the high voltage, DC. The high-voltage secondary is performed with two windings symmetrically attached by a center outlet. The voltage and current value are determined by the number of valves to be powered. Extreme safety precautions are recommended to protect against possible discharges. The voltage between ends of this winding is, on the largest of the models, more than 750v... The secondary for the rest of the filaments and dial lamps, is 6.3v with center socket and labeled 3.15-0-3.15. The center outlet connects to ground to prevent noise. (50 Hz hums.) Only in the event that it is not grinded with valve, the winding intended for the 6.3v grinder can be used for other purposes, it can be connected in series or in parallel with other filament windings, adding the intensities or voltages of both. For example on the 17032 model we can get a 6.3v and 5A winding connected in parallel or a 12.6v 2A winding if we connect them in series. To choose the most suitable transformer model for our needs, the easiest method for a given repair is the size of the same, as this usually determines the total power required by the appliance. Having the measurements of the original we will only have to choose from the three offered the closest. In the specifications of each valve, we will have the voltage and intensity values of the filaments and adding that of all the valves that the device has, we can choose from those offered. Typically the 40va model will fit 3- or 4-lamp fixtures, the 65va series for 5- or 6-valve fixtures, and the 100va series for 8- or larger ones. The Philips brand radio receiver model BE-331A, mounts the ECH42, EAF42, EBC41, EL41, and AZ41 valves, powered by a transformer referenced F2589 with the following windings: 280-0-280v at 60mA, 4v-1A, and 6.3v-2.5A. total 54va. The recommended transformer to replace it will be the 17031 since the lower model, with the same value in high voltage, the 17051, is limited in current in both high voltage and filament winding. It can be mounted upright like the original Philips brand. As the materials used in the manufacture of these transformers are of the best quality and the design complies with current regulations, the voltages are more stable, being the difference between the voltage in vacuum or with load much lower than in the old ones, which used thinner wires and wound with many more coils negatively affecting the resistance of the windings. The less resistance there will be less voltage drop on them and as a result less heat dissipation. Taking the Philips receiver mentioned above as an example, this one requires a high voltage for the rectifier of 280-0-280v at full load and the original transformer supplies 295-0-295v in a vacuum, dropping 15V when applying the load. Recommended transformer, reference 17031 provides 280-0-280v in vacuum and will hardly vary at full load as you will only be required 60mA when you can provide 90mA. In older valve-powered appliances it generates a lot of heat, which dissipates the lamps themselves and resistive components. A proof of the goodness of the materials used in the construction and calculation of these transformers is the working temperature that does not exceed 40ºC, well below what is required by the standard that accepts up to 60º.
Price: 63.6 USD
Location: Pizarra
End Time: 2024-10-09T22:15:43.000Z
Shipping Cost: 40.09 USD
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