Integrated testing module for motor-stator end-of-line testing: the guarded cell that runs hipot, insulation, impulse-winding, resistance and inductance tests through one contact fixture
Guarded end-of-line cell for motor stators · hipot, IR, impulse winding, DCR and L/Q in one fixture · 30 A spring probes · light-curtain distance S = K × T + C
In this kind of station the stator is clamped once, spring probes land on its terminals, and a scanner runs withstand, insulation, surge and resistance tests in sequence while a light curtain keeps hands out of the moving probe heads. What a buyer has to pin down is which tests share the fixture and at what levels, how the probes contact the terminals, and how the guarding is sized to the stroke.
Automated, guarded test stations built into motor and stator assembly lines that integrate the electrical tests in one clamping: AC and DC withstand, insulation resistance, impulse winding (surge) test, four-wire winding resistance, inductance and quality factor, phase or rotation check, with the contact fixture, spring probes, scanner switching, optional partial-vacuum chamber, light curtains and line software. A stand-alone bench hipot instrument is covered on the Dielectric strength (hipot) tester page; enclosed high-voltage cells for switchgear components on the High-voltage test chamber for switchgear components page; and the spheres, cups and gap electrodes of a laboratory high-voltage circuit on the Test electrodes for a high-voltage laboratory circuit page. The complete motor final-assembly line, of which such a station is one cell, is covered on the Electric motor final assembly and end-of-line test line page; mechanical run-in, torque and vibration benches for finished motors are outside this page.
CNFX editorial research · Sources checked October 13, 2026 · 3 sources
ACW, DCW, IR, impulse winding, DCR and L/Q on a stator: the test levels inside Chroma's 1920 cell
Chroma's 1920 motor stator test system is a worked example of the module: it builds a 19036 wound-component analyzer (AC and DC hipot, insulation resistance, four-terminal DC resistance and impulse winding test, with a 10-port scanner), a 3252 LCR meter for Ls, Q and winding phase, a vacuum system, a test fixture and control and data software into one station, listed as 7 in 1 with A/B DUT switching. [1]
Chroma explains why L and Q sit next to the safety tests: the Ls/Q check finds coils that run and look normal but become hotter than desired once assembled as a complete motor. A rotation check confirms that the winding connector assembly is correct, using the LCR meter, a Hall sensor or a rotor-rotation option. [1]
Chroma also offers swappable test fixtures to speed up production, alongside the A/B DUT switching. [1] The datasheet is marked preliminary and states that specifications are subject to change. [1]
20 Hz to 200 kHz; L 0.00001 µH to 9999.99 H; Q 0.00001 to 99999 [1]
List every test with its voltage, current or range, the pass limits, the order in which they run, and whether two nests are needed for the line cycle time.
02
Spring contact probes on the winding terminals: INGUN's 30 A HSS-120 with 3 N at a 4 mm working stroke
The probe heads in such a fixture carry both the high-voltage tests and the four-wire resistance measurement, so the contact needs current capacity and a defined force. INGUN's HSS-120 355 300 A 3005 high-current test probe, made for function and burn-in tests, is rated 30 A with a 3 mm gold-plated CuBe bullet-nosed tip on a 4 mm grid. [2]
Its spring data: 0.71 N pre-load, 3 N at the recommended working stroke of 4 mm, 5.3 mm maximum stroke, 32.3 mm total length, plug-in installation in KS-113 receptacles, temperature range −100 to 200 °C. [2] INGUN gives the contact resistance as Ri < 10 mΩ (typ.) in its feature list and 10 mΩ (typ.) in the electrical data. [2]
Editorial calculation: a three-phase stator contacted four-wire needs a force and a sense probe on each of its three leads, six probes; at 3 N each the probe head has to push with at least 18 N, and the fixture has to hold the part against that load. The assumption of one force and one sense probe per lead is ours; INGUN's datasheet does not state a voltage rating, so the probe's suitability for 5 to 6 kV tests has to be confirmed with the fixture builder against the clearances in the head.
Give the terminal type and pitch, the number of contacts per lead, the highest test voltage and current through the probes, and the expected cycle count before probe replacement.
03
Hipot and impulse testing under partial vacuum: why Chroma adds a 0.1 mbar pump to the cell
Chroma's 1920 can run the impulse winding and hipot tests with the stator under partial vacuum. Its reasoning rests on Paschen's law: gas corona inception voltage is nearly proportional to air pressure at a fixed gap that is not extremely short, while the pressure is not extremely low, so winding defects show up at lower test voltages and lower discharge energy when the pressure is reduced. [1]
The pump listed for the system is the VC-100: 100 m³/h nominal suction at 50 Hz and 120 m³/h at 60 Hz, 0.1 mbar ultimate partial pressure, 0.5 mbar ultimate vacuum with gas ballast, a 3.0 kW (50 Hz) or 3.6 kW (60 Hz) motor, and 66 or 69 dB(A) average noise. [1] Chroma adds that at lower discharge energy the gas discharge is visible, which can allow the defect to be repaired rather than only failed. [1]
Say whether partial-vacuum testing is required, the target pressure, and the time allowed for pump-down within the cycle.
04
Light curtains in front of the probe heads: the ISO 13855 distance S = K × T + C
Keyence's guide to ISO 13855 gives the minimum distance between a light curtain and the hazard for finger and hand detection (resolution d up to 40 mm) as S = K × T + 8(d − 14), with K = 2000 mm/s and T the machine's maximum stopping time plus the curtain's response time. If S comes out at 500 mm or more, the calculation is repeated with K = 1600 mm/s, and a result at or below 500 mm is then set to 500 mm. [3]
Keyence's sensitivity figures show where the distance comes from: one extra second of machine stopping time adds 2,000 mm, one extra millisecond of curtain response adds 2 mm. [3] In a test module, the machine stopping time in T is that of the pneumatic probe heads.
Editorial calculation: the third row reuses Keyence's 0.1157 s total stopping time with a 14 mm resolution curtain, which removes the 88 mm penetration allowance of the 25 mm example.
Case
Inputs
Minimum distance S
Keyence example, GL-R60H
d = 25 mm, response 0.0157 s, machine stop 0.1 s, K = 2000 mm/s [3]
State the measured stopping time of the probe heads and the high-voltage switch-off and discharge time, the curtain resolution, and the resulting distance from curtain to nest.
05
Data for a motor-stator integrated testing module
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Part: [stator or motor type; lead count; terminal type and pitch; variants]
Tests: [ACW kV/mA; DCW kV/mA; IR kV and limit; impulse kV and comparison method; DCR four-wire range; L/Q frequency; phase or rotation]
Sequence and cycle: [order of tests; cycle time; one or two nests]
Contacting: [probes per lead; current; force; probe life]
Partial vacuum: [required or not; target pressure; pump-down time]
Guarding: [light-curtain resolution; probe-head and HV stop time; distance; doors and interlocks]
Data: [line interface; result records; traceability per serial number]
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Share this page
Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
Which tests does an integrated stator test module combine?
Chroma's 1920 combines AC and DC withstand, insulation resistance, impulse winding test, four-terminal DC resistance, inductance, Q and phase in one station with a 10-port scanner and A/B DUT switching. [1]
What contact force does a high-current spring probe apply?
INGUN's HSS-120 355 300 A 3005 gives 3 N at its recommended 4 mm working stroke, with 0.71 N pre-load and a 30 A rating. [2]
Why test a stator under partial vacuum?
Chroma cites Paschen's law: corona inception voltage falls with air pressure at a fixed gap, so defects appear at lower test voltage and discharge energy. [1]
How far must a light curtain be from the probe heads?
Under ISO 13855 as Keyence presents it, S = K × T + 8(d − 14) for finger and hand detection, with K = 2000 mm/s; its 25 mm example gives 319.4 mm for a 0.1157 s total stopping time. [3]
Sources and what still needs a direct check
Sources checked 2026-10-13. Chroma ATE's datasheet and product page for its 1920 motor stator test system and the 19036 analyzer inside it, HUBER+SUHNER INGUN's datasheet for a 30 A high-current spring contact probe, and Keyence's guide to light-curtain safety distance under ISO 13855.
