One customer gave us a problem: the customer's power system carrier communication uses a set of capacitors, the requirements are: the total rated voltage is 50KV, the total capacity is 50,000 to 20000PF. The frequency is 30MHZ, there is no special requirement for current. Because the current is small. How to equip this group of capacitors?
For the customer's problem, the engineer quickly gave the answer: use CT81 lead-type ceramic capacitor, XL material, nominal voltage is 15KV, nominal capacity is 2200PF. Frequency characteristics are greater than 30MHZ. Usage: First adopt parallel connection 10 capacitors are connected in parallel as a group, a total of four groups. After parallel connection, the rated voltage of each group of capacitors is 15KV, and the capacity rises to 22000PF. Then, four capacitor groups are connected in series, and after series connection, the voltage rises to 60KV, and the capacity decreases. To 5500PF.
When the guest listens to the parallel connection and the series connection, it means that it is unacceptable. They want only the parallel connection in the circuit, there is no series connection. Moreover, they want to suspend the product in the air, so I hope that the whole capacitor combination is as small as possible.
The customer's demand is the command. The engineers immediately use their brains: Why not use bolt-type capacitors? Although the guests do not require large currents, we can provide bolt-type capacitors with large current carrying capacity!
Therefore, a new solution came out immediately: CT8G bolt capacitor, rated voltage 50KV, maximum withstand voltage over 80KV, customer capacity 2200PF. The diameter of a single capacitor is 60MM, thickness is about 34MM. According to the actual needs of guests, guests can Determine the number of capacitors in the capacitor combination. For example, if only 10000PF is needed, use 5 capacitors in parallel, which becomes a 50KV10000PF capacitor combination. If you think you must reach 22000PF, you can use 10 50KV2200PF capacitors in parallel. In terms of the above, the stability of the bolt type is better, the current capability, the voltage capability, and the temperature characteristics are better than the lead type.
The guest is always shrewd. After listening to our new plan, he is very happy: this plan is good, according to your two quotations, obviously the bolt type is more economical! In fact, the price of the lead type capacitor 40 has exceeded The price of 10 bolt-type capacitors! We have done so. We have not thought of the cost!
Next, the guest requested proofing. This XL high-voltage ceramic capacitor is not used in bolt-type capacitors. This is a pure high-frequency capacitor material. More importantly, it can generally reach 2200PF capacity. The ceramic material rarely reaches 30MHZ. XL is the only one. Of course, 2200PF is already the limit. If the customer wants a higher capacity, it is impossible.