Coil Voltage
The nominal supply voltage a valve coil is designed for; in mobile hydraulics commonly 12 V or 24 V. Even if two coils look physically identical, the winding wire gauge and number of turns differ, so a wrong match results either in weak pull or in a burned winding.
What is needed to produce the same magnetic force is the ampere-turn product. A 24 V coil produces the same force with thinner wire and more turns, therefore with higher resistance. The consequences are as follows:
- If you give 12 V to a 24 V coil: the current halves, the force is not enough, and the spool either does not open at all or stops halfway.
- If you give 24 V to a 12 V coil: the current doubles, the heat jumps to roughly four times, and the winding insulation breaks down in a short time.
The label on the coil states the voltage and usually the power rating; if the label is unreadable, a resistance measurement largely distinguishes the type. On the AXI product side, do not forget this distinction: the HCT400 runs on a 12 V supply and full performance is given between 10-18 V; the HCT402 is designed to be usable directly on 12 V and 24 V systems. These values belong to the kit's supply, not to the vehicle's valve coil.
Where this term is used: What Is a Hydraulic Lever Retrofit Kit? Definition, Components, Operating Principle