A4VSO500DFR/30L-PPB13N00 Hydraulic pump German Rexroth piston pump original

💡 DFR Control Explanation:​ DFR is a Load Sensing (LS) + Pressure Limiting (DR)​ control. The pump maintains a constant pressure differential (∆p, typically 14–18 bar set by internal spring) between pump outlet (P) and the Load Sense signal (LS port)​ from the directional valve stack — delivering only the flow demanded. A built-in pressure limiter prevents exceeding the mechanically set maximum pressure. Unlike DFR1 (externally plugged LS), DFR typically has the LS port ready for connection to the valve bank's LS line.

FAQ — Frequently Asked Questions

Q1: What does "DFR" control mean and how is it different from DR, LR2, or EO1?

A:​

• DFR​ = Load Sensing + Pressure Limiter​ with internal spring setting the LS differential (∆p). Requires LS line from valve bank. Most common for standard LS systems.

• DR​ = Pressure compensator only (no LS) — pump goes to max displacement below set pressure, then de-strokes.

• LR2​ = Same LS+DR principle but may offer different orifice/spring options; functionally close to DFR in many cases.

• EO1​ = Electro-hydraulic pilot control — no internal LS spring, needs external pilot pressure.

  DFR is the standard choice when you have a valve bank providing a Load Sense signal.

Q2: The rotation code is "L" (30L) — what does that mean practically?

A:​ "L" = Counter-Clockwise​ when viewed from the drive shaft end. This is the opposite of the more common "R" (Clockwise). The pump must be driven in this direction​ — running it in reverse will cause immediate failure due to loss of lubrication and improper suction. Always verify your prime mover / coupling rotates counter-clockwise from the shaft side.

Q3: What are the suction (inlet) requirements for this 500 cc pump?

A:​ With 500 cm³/rev displacement, inlet conditions are critical:

• At 1200 rpm, inlet absolute pressure should be ≥ 1.0–1.2 bar​ (boost pump strongly recommended for sustained high-speed operation).

• For speeds >1200 rpm, a dedicated charge pump / supercharge circuit​ is essential to prevent cavitation.

• Use generously sized inlet piping (≥ DN80/100), minimize elbows/restrictions, and fit a 149 µm (100 mesh) suction strainer.

Q4: Can I mount an auxiliary pump (gear pump) on the rear?

A:​ No.​ The suffix N00​ indicates no through-drive shaft. The rear of the pump housing is blanked. If you need a through-drive for a charge / pilot gear pump, select a version with a through-drive code such as K01, K02, etc.

Q5: How should the case drain (L port) be handled?

A:​ Connect one case drain port​ directly to the tank with a dedicated line — zero backpressure​ (max 0.5 bar). The second drain port must be plugged. Route the drain line to above the tank oil level or provide a loop to prevent air ingestion. A blocked or pressurized drain = shaft seal failure.