Technical explanations for solenoids
Detailed explanations and descriptions help you to design more precisely and use a DC solenoid and better understand its properties.
Magnetic coils for DC voltage and AC voltage
All DC solenoids from Kuhse are equipped with DC voltage coils. With the corresponding electronic circuitry, which is partially integrated into the solenoid, the solenoids can also be designed for connection to a corresponding AC voltage.
Solenoid: direct current or alternating current?
A DC solenoid offers several advantages over an AC solenoid. The solenoid, for example, is generally machined out of a massive body. The current consumption is constant over the entire stroke, which therefore allows the solenoid anchor to be stopped in any position.
There is no need to operate the unit to the stroke end position (stop), since the
risk of burning through the coil is marginal. However, the required force, which reaches its highest level at the end of the stroke, must be closely examined.
The enamelled copper wires and insulation materials used are extremely temperature-resistant and designed for high thermal class requirements (e.g. thermal class F). The exact design of the coil is derived from the individual conditions of the installation location or special necessary certifications.
The bearing is self-lubricating and therefore absolutely maintenance-free. Please refer to our corresponding operating instructions for more detailed information concerning operation.
In our standard design, the metallic surfaces are galvanised and blue passivated (RoHS-compliant). Applying higher-quality coatings from our product range achieved even greater corrosion protection.
Magnetic force (lifting force)
Magnetic force is the available part (i.e. reduced by frictional losses), which is generated in lifting solenoids in the horizontal lifting direction of mechanical force. The magnetic force values included in our lists apply for coils at operating temperature and at 10% undervoltage. At 100% rated voltage, the specified forces increase.
In addition, the specified forces apply in a horizontal installation position. If the solenoids are not installed horizontally, the respective weight of the anchor to the magnetic force must be added or subtracted.
This value in our tables for the stroke and force specification is at 0 mm of travel. This force moves the solenoid to its stroke end position. Some DC solenoids are equipped with components for silencing noise in the stroke end position.
Stroke is the useful travel that raises the solenoid anchor to its maximum position. It is not necessary to use the complete stroke.
In its exact definition, the lifting work W is the integral of the magnetic force F over the solenoid stroke s. The values specified in the tables have been approximately calculate by the product W x s and always refer to the maximum stroke.
By heating the exciter coil, the DC solenoids may heat up to a considerable extent. Under unfavourable conditions, the surface temperature can reach well above 100°C.
Attention: Protect solenoids against making contact with anything. The high surface temperature can result in burns.