A factory acceptance test is the only point in the procurement cycle where you can watch the machine work while the consequences are still someone else's problem. Yet most FATs consist of a short run, a photograph and a signature. For a machine that will hold 250 kN sustained over a river crossing, that is not a test, it is a handover with the risk transferred to you.
Contractors rarely discover a machine's real limits at the factory. They discover them on the third pull, when the oil temperature will not come down, the brake creeps under sustained load, or the pull at maximum speed turns out to be far below the datasheet. A properly staged FAT surfaces all three in half a day, with calibrated instruments and the manufacturer's engineers present.
Machines are limited by thermal steady state, not by a single pressure reading. At 25 percent load the test reveals control stability and minimum speed behaviour. At 50 percent it shows efficiency and the rate of heat build-up. At 75 percent it shows whether the cooler can hold the approach to steady state. At 100 percent of sustained rating it shows whether the oil temperature plateaus or continues climbing. The final stage is the one that separates a genuine continuous-duty machine from one with an optimistic datasheet.
| Stage | SA-QY120 (100 kN continuous) | SA-QY150 (120 kN continuous) | What it proves |
|---|---|---|---|
| 25 percent | 25 kN | 30 kN | Low-load stability, minimum speed control |
| 50 percent | 50 kN | 60 kN | Efficiency, heat build-up rate |
| 75 percent | 75 kN | 90 kN | Cooler adequacy approaching steady state |
| 100 percent | 100 kN | 120 kN | Sustained capability, oil temperature plateau |
| Peak check | 120 kN brief | 150 kN brief | Relief setting, structure under peak |
For a high-capacity machine the same staging applies to much larger numbers: the GS280 is published at 280 kN maximum tractive force and 250 kN maximum sustained traction at 2.5 km/h, so the 100 percent stage is 250 kN sustained and the peak check is 280 kN. On the tensioner side, the GL140TP is published at 140 kN maximum intermittent tension and the 8 ton twin-bundle tensioner at 2×45 / 1×90 kN intermittent against 2×40 / 1×80 kN continuous.
Two practical checks are often skipped. First, hold each stage long enough to reach thermal steady state rather than a fixed five minutes, because a cooler that looks adequate in five minutes may fail at forty. Second, witness the test with your own instrument: a handheld dynamometer or calibrated load cell in the line costs little and converts the manufacturer's claim into a number you can hold. If a supplier resists either request, that is itself information about the machine and about the support that follows delivery.
Reference configurations: the GS280 280 kN puller rated 250 kN sustained, the 280 kN hydraulic brake cable puller winch, the SA-QY120 120 kN puller and the 16 ton four-conductor tensioner.
For a high-capacity puller or tensioner, plan a full day. Staged loads to thermal steady state consume three to four hours before brake and instrumentation tests begin.
No. Video shows the machine running; it does not show pressure at each stage or the oil temperature curve. Ask for the data.
It should be, for critical crossings, but it cannot replace the factory test, where calibrated load is available, corrections are still possible and the manufacturer's engineers are standing next to the machine.
Người liên hệ: Mr. Marble Wu
Tel: 8613301534008
Vietnamese
