Selecting an HPU starts with the brake’s required release pressure and flow. You must provide enough pressure to overcome spring force and enough flow to achieve the needed response time (how fast the brake releases). Consider the number of brakes served by one HPU, whether they operate simultaneously, and the required duty cycle.
Key parameters include: rated pressure, pump flow rate, reservoir volume, filtration level, valve configuration (directional valves, check valves, pressure relief), accumulator needs (for emergency release or quick response), and monitoring (pressure switches, level/temperature sensors). Environmental conditions matter—cold sites may require heaters; offshore sites may require corrosion-resistant enclosures and higher IP ratings.
Also consider safety philosophy. Many fail-safe brake systems require brake release only when power is present; however, some applications need controlled release during maintenance or rescue, which may require manual pump provisions. Finally, ensure compatibility with hydraulic fluid type and cleanliness targets (ISO cleanliness codes). An undersized or poorly filtered HPU is a common root cause of slow release, unstable braking, and high maintenance.
