MEIDEN Vacuum Capacitors / VC (Vacuum Capacitors)

Handling Precautions

Before Use

1. The Meiden Vacuum Capacitors are properly packed for shipping, to protect them from strong impacts during transport. However, an external shock may damage the internal functions of the capacitors. Therefore, recheck their capacitance and withstand voltage values before mounting. Check for the damage, if any. The capacitors can withstand impacts of up to 294m/s2. Never drop the capacitors or handle them carelessly in such a manner that may apply stronger impacts to them.
2. To prevent flashovers, wipe the insulating part of the capacitors with cloth (dry or wet with alcohol) and to remove moisture and dust. At that time, do not use solvents containing chlorine (e.g.: trichloroethane).
3. If dust or contaminants stick to any other parts, wipe them off with dry cloth.

Mounting Vacuum Capacitors

1. When installing the capacitors in equipment, make sure not to apply any bending stress greater than 1225N・cm. In particular when supporting the capacitors on both fixed and moving sides, mounting fittings on either side should be made of a soft material in flexible structure in order to protect the capacitors from their thermal expansion and external stresses.
2. When using a motor to turn the capacitors, use a flexible coupling to prevent the lateral load to the capacitance adjustment shaft. When using an inflexible coupling, a central misalignment of up to 0.2mm is permissible. A greater misalignment may result in irregular turns.
3. When an optional guide bearing (available separately) is used for the VM type capacitors, it is delivered in a shipping style, attached to the capacitors with two screws (diagonally to each other). As it is secured in an optimal position (that ensures central alignment of the capacitance adjustment screw), use the assembly without removing it.
4. If you want to use a guide bearing of your own, it should be designed based on the premise that a misalignment of a maximum of ±1mm may remain between the capacitance adjustment screw and the M5 taps.
5. The maximum allowable torque of the M5 taps on the fixed and moving sides is 147N・cm and that of the M4 taps is 71.6N・cm. Tighten the taps to lower the torque values.

Using Vacuum Capacitors

1. The maximum allowable vibration level of the capacitors is 98m/s2. Do not apply greater vibration levels to the capacitors.
2. When the surface temperature of the capacitors exceeds 125℃, an abnormal current may be carried. If the surface temperature is expected to rise high, use optional water-cooled flanges.
3. Do not place a metal object with an electric potential close to the sides of the ceramic envelope of the capacitors, as it may affect the capacitors and generate a flashover. Secure a sufficient space around the ceramic envelope.
4. Do not use the capacitors in environments where corrosive gases (particularly sulfur and chlorine) or dust may exist. The surface of the capacitors may give rise to discoloration, or in some cases the properties of the capacitors may be affected.

Small "Thump" Noise … Anything Wrong?

A "collision" noise may be generated when the ceramic center pin located inside the capacitors hits both ends. It is sometimes heard when the capacitance adjustment shaft is rotated in vertical orientation. There is, however, no problem in actual performance.

Squeaky Sound

A squeaky sound may be generated when the ceramic center pin in the capacitors slides. There is, however, no problem in actual performance.

Product Types

Custom-Ordered Vacuum Capacitors

MEIDEN has a variety of vacuum capacitor lineups with various specifications.
We will try to accommodate your special requirements as much as possible. Please feel free to contact us.

Provision of Technical Information

1. This catalog contains only a portion of technical information. MEIDEN reserves the technical data sheets to provide the dimensional outlines (drawings), frequency-current characteristics, and tuner turns-capacitance characteristics of all vacuum capacitors.
2. In your consideration of purchasing the MEIDEN Vacuum Capacitors, make sure that you are keeping up with the latest edition of the data sheets because they are subject to change for product improvements without prior notice.