Yamaha’s engines are famous for being very torquey and potent, with it’s 708cc being no exception. that engine is also famous for being very reliable given its power numbers. And a much higher resistance total too.Combine this with Yamaha’s Ultramatic transmission and you got yourself a beastly UTV that is going to be revving for years without an issue. This would really eat up the winding space then for the common mode choke windings. Only way around would be to use common mode inter-connect chokes on each of the multi-filar windings so that they can be common moded in the layup. The bifilar or multi-filar approach seems only useful to me if the windings have similar AC and DC structure so that the insulation can be kept to a minimum. With a long E lamination this can be further lengthened until the leakage path is nearly the same length as thru the lamination, so most flux will stay in the lamination where it is wanted. ![]() This makes for long magnetic path length with low leakage inductance. ![]() The conventional layered approach has the wires snugged together for each layer so that magnetic leakage pathes have to travel the length of the layer. The secondary wire has a short local magnetic leakage path around thru the thick wire insulation. It seems to me that using similar insulation thickness on the secondary wire (relative to interlayer insulation), with multifilared primary wires enclosed around it, can be made equivalent in distributed capacitance to the conventional layered insulation approach.īut the leakage inductance needs to be looked at carefully then. Then it is back to the old juggling competition. The only simple way to improve the filar config (as I see it), would be to use say four or eight insulated primary wires to each secondary wire - on each layer - the separate primary windings would then be connected in series. Of course layer insulation distance etc, etc all contribute to making a comparison not so simple. Each layer could be wound so that secondaries are positioned directly above each other to minimise intra-layer coupling (simple view only).Ī layer winding configuration (Interleaved secondary between two sections of primary)would have each secondary turn next to primary (under and over layers) with an effective length of the secondary wire.Ī very simplisitc comparison would see that the interleaved layer configuration would have 1/18 the capacitive coupling (using Pieter's 18 layer example), which would then be about 1/4 the high frequency bandwidth. It is worthwhile attempting to clarify the capacitive coupling comparison - in a very simple way - for a better understanding and insight.Ī filar winding configuration would have each turn of the primary effectively placed next to the same wire 'length' of secondary (both sides of secondary wire would see a primary wire. For high impedance tubes like the 813, but also 845, GM70, 211 and others the number of sections will be less than for tubes like 2A3, 300B with Rp under 1k. IMHO the only way to achieve acceptable results is a balanced configuration of primary and secondary sections not based on bifilar or trifilar winding techniques. A 6C33 might get away with this, not the 813.Ī transformer like this will show HF loss under 20 kHz (but because of the distributed coupling it will be without HF resonance ). These 17 nodes are too many for this pretty high impedance application. This means we have 17 nodes where capacitive coupling from primary to secondary ground will compromise the HF bandwidth (one of the 18 nodes, B+, will not harm as it sees secondary ground). With your proposed trifilar winding configuration using insulated wire we have to wind a stack of 18 layers, whereby all primary windings are connected in series, and all secondary windings are parallel connected. For this tube in triode 10k4 related to 8 ohms would be a sensible impedance ratio (winding ratio 36:1). Presume we have to wind the 813 output transformer.
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