Frequently Asked Questions
Q1: What does "LR2" control mean and how is it different from DFR/DFR1?
- LR2 = Purely hydraulic Load Sensing + Pressure Limiter. It requires an external Load Sense (LS) line from the valve bank connected to the pump's LS port. The pump delivers only the flow demanded by the valve, saving energy. No electrical input is needed for basic operation.
- DFR/DFR1 = Same LS principle but with an integrated spring defining the ∆p and an adjustable pressure limiter -- often simpler for standard applications. LR2 gives more flexibility in LS signal conditioning and is common in large mobile or industrial systems with distributed valve banks.
Q2: The rotation code is "L" (30L) -- what does that mean practically?
"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 large displacement pump?
With a 355 cc displacement, proper inlet conditions are critical:
- At 1500 rpm, inlet absolute pressure should be ≥ 0.8-1.0 bar (supercharge preferred for sustained high speed).
- For speeds >1500 rpm, a boost pump is strongly recommended to prevent cavitation.
- Keep inlet line short, generously sized (≥ DN65/80), and avoid restrictions. Use a 149 µm (100 mesh) suction strainer.
Q4: Can I mount an auxiliary pump (gear pump) on the rear?
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?
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. The case drain line should be positioned above the tank oil level or looped to prevent air ingestion. A blocked drain = shaft seal failure.
Q6: What drive motor power is required?
At 1500 rpm, 350 bar, and 355 cc:
- Theoretical hydraulic power ≈ (355 × 10⁻⁶ × 350 × 1500) / 600 ≈ 310 kW
- Including mechanical losses (~90%), input power ≈ 345 kW
Recommend a 355 kW (≈475 HP) prime mover with adequate starting torque reserve for 400 bar peak conditions.
Q7: Is the standard NBR seal okay for water glycol (HFC) or phosphate ester (HFD)?
Standard NBR is compatible with HFC (water glycol) with pressure/temp derating. It is NOT compatible with HFD (phosphate ester) -- for HFD you need FKM (Viton) seals, which would be a custom order (typically with /V suffix). Confirm with Rexroth if your fluid is not mineral oil.
