Temperature rise is one of the fastest ways to turn a “correctly sized” industrial brake into a reliability problem. Excess heat accelerates lining wear, hardens seals, changes friction behavior (fade), and shortens the life of coils, thrusters, and hydraulic components. If you want repeatable braking torque and predictable maintenance intervals, you need a temperature rise test that matches real duty—not a generic bench run.
This article explains how to design an industrial brake temperature rise test with practical calculations, test-cycle design, sensor placement, and clear pass/fail criteria. Examples are mapped to typical use cases of our products such as YWZ13 electro-hydraulic drum brakes, YPZ2 electro-hydraulic disc brakes, and SH hydraulic fail-safe disc brakes.
[Image Placeholder] Test stand overview: motor + inertia + brake assembly + data acquisition (DAQ) + airflow direction arrows.
1) Define the test objective (what decision will this test support?)
Before selecting sensors or writing a test cycle, define the decision you want to make, because the duty cycle and acceptance criteria will differ:
- Type/Design validation: confirm a brake design can survive a target duty cycle without overheating or fading.
- Production acceptance: verify each unit meets a controlled thermal and functional baseline (shorter run, tight repeatability).
- Application verification: simulate a customer’s machine duty (most valuable for sales + engineering, because it reduces commissioning risk).
In crane, hoist, conveyor, and wind applications, a useful temperature rise test usually covers both: (1) repeated dynamic stops (heat generation) and (2) hot holding/parking behavior (heat soak + static torque verification).
2) Collect the four numbers that drive heat
To design a duty cycle that represents real operating heat, you need the following four inputs at (or reflected to) the brake shaft:
- Speed at brake engagement (rpm)
- Equivalent inertia (kg·m²)
- Stops per hour (or cycle frequency)
- Braking time per stop (s)
If you only have motor nameplate data, you can still estimate—but inertia is the parameter people most often miss, and it’s usually where thermal problems originate.
| Input | What it means | How to get it (practical) |
|---|---|---|
| Speed (rpm) | Brake engagement speed at the brake shaft | Encoder/VFD feedback; or motor rpm ÷ gear ratio |
| Inertia J (kg·m²) | Total reflected inertia seen by the brake | Drive model, OEM data, or measured coast-down test |
| Stops/hour | How often the brake absorbs energy | PLC logs; operator cycle data; video timing |
| Stop time (s) | Sets peak power & shock | Control requirement, safety limit, or measured stop time |
3) Convert duty cycle to energy and thermal load (simple math that changes everything)
Once you have speed, inertia, and stop frequency, you can estimate how much energy the brake converts into heat.
Energy per stop (rotational system):
E_{stop}=\frac{1}{2}J\omega^2Average braking power (strong predictor of steady temperature rise):
P_{avg}=E_{stop}\times\frac{N}{3600}Peak braking power (useful for fade risk and “hot spots”):
P_{peak}=T\times \omegaWorked example you can copy into a spreadsheet
Assume a travel mechanism where the brake sees: J = 40 kg·m², speed 800 rpm (ω ≈ 83.78 rad/s), and 30 stops/hour.
Then: Estop ≈ 0.5 × 40 × 83.78² ≈ 140 kJ. Average braking power Pavg ≈ 140,000 × 30 / 3600 ≈ 1.17 kW.
This “~1.2 kW average” is often the difference between a brake that stabilizes at 110°C vs. one that climbs past 180–220°C depending on airflow and friction material.
4) Define boundary conditions (ambient, airflow, mounting) or your test won’t be repeatable
Thermal results can swing dramatically with airflow and installation geometry. Two labs can run “the same test” and get very different temperatures if one has a fan blowing across the brake and the other does not. Set and record these boundary conditions:
- Ambient temperature: record and control if possible (e.g., 20–30°C). Always report ΔT, not only absolute temperature.
- Air velocity at brake: measure with an anemometer. Even ~0.5–1.5 m/s airflow can significantly reduce peak temperatures.
- Mounting orientation: vertical vs horizontal can change heat soak into structure and oil reservoirs.
- Enclosure effect: “open frame” vs “guard cover” changes convection. If your application uses a cover, test with it.
[Image Placeholder] Airflow measurement points (front/back of brake, near thruster motor, near disc/drum surface).
Report temperature as rise above ambient:
\Delta T = T_{max}-T_{ambient}5) Instrumentation plan: where to measure temperature (minimum channels that actually catch problems)
A temperature rise test is only as good as sensor placement. Use Type-K thermocouples for trend data and an IR camera to validate surface hot spots. A practical sampling rate is 1 Hz (1 sample/second) for stop-cycle testing.
For electro-hydraulic drum/block brakes (e.g., YWZ13 series)
- Brake wheel outer surface near the rubbing track (2 points, 180° apart)
- Lining backing plate near friction surface (at least 1 point per shoe)
- Brake arm/structure near pivot (binding/drag heat path)
- Thruster motor housing temperature
- Thruster cylinder body / oil zone temperature (if feasible)
- Ambient air near brake (shielded from radiant heat)
[Internal Link] YWZ13 Series Electro-Hydraulic Drum Brake
For disc brakes (e.g., YPZ2 series / SH series fail-safe)
- Disc temperature (IR camera on friction ring) + one thermocouple on disc hat/near ring
- Caliper body near pad carrier (left/right)
- Pad backing plate (near friction interface)
- Hydraulic unit / actuator housing temperature (if applicable)
- Ambient
[Internal Link] SH Series Hydraulic Fail-Safe Disc Brakes
Tip: If your brake “passes” but customers still report overheating, you’re often missing the real hot spot—commonly a dragging interface or a small area of the disc/wheel that overheats first. That’s why IR spot validation is worth doing even with a simple thermocouple setup.
6) Build duty cycles that match how the brake heats in real life
Do not use one generic cycle for all brakes. Travel mechanisms, hoisting mechanisms, and wind yaw systems all heat differently.
| Scenario | Suggested cycle structure | What it reveals |
|---|---|---|
| Crane travel / trolley travel | Run 30–60 s → brake 2–6 s → dwell 10–30 s → repeat | Thermal stability under frequent medium-energy stops |
| Hoist duty (with VFD) | Controlled decel via drive + brake set at near-zero speed; include hot holding stage | Heat soak, holding stability, brake timing sensitivity |
| Emergency stop verification (if rated) | After stabilized temperature: 1–3 high-energy stops with defined cool-down | Fade risk, peak hot spot behavior, post-event recovery |
Example cycle math (quick reality check): If your cycle is Run 30 s + Brake 3 s + Dwell 20 s, each cycle is 53 s, which is about 68 stops/hour. This helps you translate “operator behavior” into a repeatable lab plan.
7) Define “thermal stabilization” so you don’t stop the test too early
A common mistake is running 10–20 stops and calling it “temperature tested.” For a meaningful temperature rise result, run until the hottest measured point stabilizes under the same cycle. A practical stabilization rule is:
- Consider the brake stabilized when the hottest channel changes by ≤ 2°C over 10 minutes (or ≤ 1°C over 5 minutes) under the same duty cycle.
This gives you a repeatable stop condition across tests and makes data comparable between brake types (drum vs disc) and product configurations.
8) Pass/fail criteria: combine temperature + performance (temperature alone is not enough)
A robust acceptance decision should include:
- Component temperature limits (coil/thruster/hydraulic oil/friction interface)
- Torque retention at stabilized temperature (fade control)
- Release quality (no dragging at hot condition)
- Post-test condition (no abnormal glazing/cracking/scoring)
8.1 Practical temperature limit references (use datasheets as final authority)
Exact limits should come from your brake and component ratings, but these typical engineering references help you set realistic gates:
- Coil winding temperature: should remain below insulation class limits (e.g., Class F ≈ 155°C, Class H ≈ 180°C at winding hot spot). Housing temperature is usually lower than winding hot spot.
- Electro-hydraulic thruster oil zone: many systems target < 70–90°C for seal life and stable response (confirm your oil/seal spec).
- Friction interface (depends on lining): organic materials typically need lower continuous temperatures than semi-metallic or sintered formulations. Use your lining data sheet if you want defensible acceptance criteria.
8.2 Torque retention (fade check at hot condition)
If you can measure torque directly (torque sensor/dynamometer), compare hot vs cold performance. If you cannot, use stopping time with a known inertia as a proxy.
\text{Torque Retention}=\frac{T_{hot}}{T_{cold}}\times 100\%Many industrial teams treat a reduction greater than 10–15% (at stabilized temperature) as a meaningful warning signal—especially for safety-critical stops. Your actual acceptance threshold should match your risk level and standard.
8.3 Dragging check (the hidden heat source)
A brake that doesn’t fully release will “pass torque” but fail in the field due to overheating. After the system reaches stabilized temperature, include a short verification stage:
- Run at target speed with brake commanded fully released for 5–10 minutes.
- Confirm motor current does not drift upward.
- Confirm brake temperatures do not continue to climb abnormally (a rising trend during “no braking” is a strong drag indicator).
9) Post-test inspection checklist (turn data into maintenance insights)
After the thermal cycle, inspect and document what changed. This is where test data becomes useful for both engineering and customers:
- Lining wear measurement (mm) and wear uniformity
- Glazing, cracking, delamination, oil contamination
- Disc/brake wheel surface: scoring, heat spots (blueing), runout (if suspected)
- Thruster leakage, oil condition, seal condition
- Fasteners and pivots: looseness, abnormal play, binding
[Internal Link Placeholder] Download: Brake Temperature Rise Test Record Template (Excel/PDF)
10) Product-focused testing notes (how we usually validate our brake families)
YWZ / YWZ13 electro-hydraulic drum brakes: In addition to drum temperature, we pay close attention to shoe clearance stability and thruster temperature. Many overheating complaints trace back to partial release, linkage binding, or incorrect adjustment—your test should always include a hot-condition drag verification stage.
YPZ2 electro-hydraulic disc brakes: Disc systems often run cooler overall, but can develop local hot spots if alignment or disc runout is poor. IR validation is particularly valuable here, because one thermocouple can miss a hot band near the pad edge.
SH hydraulic fail-safe disc brakes: For fail-safe systems, the hot holding behavior matters as much as stop temperature. We recommend including a hot holding stage (e.g., 10–30 minutes at defined holding torque) to confirm there is no creep and release remains reliable after heat soak.
Need a temperature rise test plan for your exact brake model?
If you share (1) brake model, (2) speed, (3) estimated inertia, (4) stops/hour, (5) lining type, and (6) ambient/enclosure conditions, we can draft a practical test matrix (cold + stabilized + hot holding) with a pass/fail checklist for your project.
[Internal Link Placeholder] Contact our engineering team to build your application-specific thermal test cycle.
