Note from Magès to Cadiou: endurance results for 2.2 cm³ hydraulic motors (19.12.1962)
A handwritten note from Paul Magès to Mr. Cadiou recording the initial endurance test results for 2.2 cm³ hydraulic motors, some exceeding 5,000 hours of operation in the Laboratory.
Understanding this document
In this document
This handwritten note is addressed by Paul Magès to Mr. Cadiou, with the heading mentioning "MM. Sallot - Sesnec" p. 6. It concerns hydraulic motors with a displacement of 2.2 cm³, and its purpose is to communicate, "for information", the endurance test results obtained "as of 19.12.62" on motors running in the Laboratory p. 6.
The oil used is specified: "BPI a (mineral) at 60°C" p. 6.
Motors driving a DS fan
A first table provides, for five numbered motors, the rotation speed, test pressure, and the endurance duration obtained:
| No. | Speed / Pressure | Duration obtained | Page |
|---|---|---|---|
| No. 2 | 3500 rpm - 150 kg/cm² | 3200 hours | p. 6 |
| No. 4 | 3700 rpm - 150 kg/cm² (except for drive incident at 2480th h.) | 4580 hours | p. 6 |
| No. 5 | 3920 rpm - 150 kg/cm² (shaft ring changed at 1000 and 2250 h.) | 2720 hours | p. 6 |
| No. 6 | 4000 rpm - 150 kg/cm² | 3470 hours | p. 6 |
| No. 9 | 3500 rpm - 110 kg/cm² | 5030 hours | p. 6 |
Motor braked by a HPDS pump
A second group of tests follows a specific cycle: "speed 0 → 3500 → 0", "Pressure 0 → 150 kg/cm² → 0", at a rate of "31 cycles / hour" p. 6. The results for two motors are:
| No. | Duration obtained | Page |
|---|---|---|
| No. 1 | 5610 hours | p. 6 |
| No. 7 | 4870 hours | p. 6 |
The page features crossings-out ("pour ac", "et leur durée", "obtenu") typical of rapid, working drafting.
Context
The acronym DS likely refers, in the Citroën context, to the famous DS saloon, whose fan could be driven by a hydraulic device — an innovation path explored alongside the hydropneumatic suspension developed by Magès. The mention HPDS probably refers to a high-pressure pump linked to this same vehicle, although the document does not detail this acronym.
These tests took place during the period when Citroën laboratories were testing various applications of hydraulic technology — cylinders, pumps, motors — beyond just the suspension, as part of an exploration of the "hydraulic path" specific to the brand during the 1960s-1970s.
Archivist's perspective
This document is a fairly raw piece of technical work: it is a simple record of results, without discourse or developed conclusion, which makes it a direct and unretouched testimony of testing activity at the Laboratory in December 1962.
The durations reached, exceeding 5000 hours for some motors (No. 1, No. 9), suggest tests conducted over several months, or even years before this note — it seems that these small-displacement motors were monitored continuously and rigorously.
This document is in the same experimental vein as other items in the collection dedicated to endurance tests, such as the Endurance test monitoring of the 2 CV A12 with hydrostatic transmission, which attests to a similar method of long-term monitoring of hydraulic components at Citroën.
In the same folder
Dating
19 December 1962
Document
1 page
Source: « Scanner 18 août 2025 à 15.25.pdf », p. 6
Category
Archival note
p.6 heading "Magès to Mr. Cadiou" and date 19.12.62.