I would put a hold on this order. There are two torque figures in the file and neither says which shaft it belongs to. One is 720 N·m and the other is 120. Both could be right. If the belt pulls with 4,000 N at a radius of 180 mm, it puts 720 N·m on the pulley. Now draw the 6:1 gearbox in between. If the brake is on the input, the ideal calculation gives one sixth of that at the brake. Put the brake on the output and the smaller number doesn't apply. That's quite a difference to leave to an assumption on a purchase order.
The other line I'd send back is “release pressure OK.” At which port? At what time? Suppose the branch supply gauge read 30 bar. The reading we need is at the brake, and the part that matters is the first fraction of a second. In the made-up trace here, the shaft begins to turn at 0.70 s and the full-release condition is recorded at 0.92 s. The steady reading a mechanic sees a second later tells us nothing about the gap. Check the test point and compare the trace with the brake data before blaming the motor for a slow start.
A new unit could fit every hole in the flange and still have a different release requirement. Get the supplier to name the brake option and show the port on the drawing. Write the actual load case and the point where the brake is supposed to take it on the same sheet. If the pack has to stop a moving load after a pressure loss, that belongs in the request too. Otherwise the supplier may reply with a holding figure when the real question is about what happens before the shaft has stopped.
Start at the part of the conveyor that can still move
The first question is what the belt does after the pump stops sending oil. On an incline it can still pull on the drive. Take the load path from the pulley back through the gearbox until you reach the brake. Mark that shaft on the drawing. On a second drawing, mark the hydraulic parts that control the belt while it is still moving. Those are the two bits of information I'd want before deciding whether the quotation describes the job.
A conveyor stopping normally and one losing oil supply can get to a parked state in different ways. During a normal stop the circuit might slow the belt before the pack closes. After a fault the pack might apply while it is still moving. The equipment maker has to say what happens in that case. A passive parking brake is rated for holding at rest. Where a brake is expected to stop movement, the supplier needs the speed, energy and duty for that particular event. Some industrial brake packages cover both functions, with separate conditions for each. Twiflex hydraulic brake packages
On the drawing
Question that has to be answered
The belt is parked with load on it
Where does the holding torque act?
The motor is slowing the load
What carries the load up to the point of brake application?
The belt starts while loaded
When does the drive take the load relative to release?
Power or pressure is lost
Does the brake apply with the shaft still moving?
A useful stopping specification keeps the sequence and the ratings beside each other. If the equipment owner says the brake never stops movement, ask where that condition is established in the fault review as well as in the normal stop. If the unit does have a moving duty, get it onto the purchase request before the supplier compares the holding numbers.
Both torque figures can be right
Suppose 720 N·m and 120 N·m turn up in the same file. With no shaft label, I would send the figures back. Here is one way they could both be right. Imagine the stationary belt pulls tangentially on the pulley with 4,000 N, and the effective radius is 0.18 m. That puts 720 N·m on the pulley. Now draw a 6:1 reduction between the pulley and the brake. Six input turns to one output turn gives a reflected input torque of 120 N·m with ideal gearing. A brake on the pulley still sees the 720 N·m. Which of the two numbers applies to the quote depends on where the pack sits.
Entry for the hypothetical conveyor
Value
Location
Stationary belt force
4,000 N
Tangential at the pulley
Effective radius
0.18 m
At the line of action
Force times radius
720 N·m
Pulley shaft
Reduction ratio
6:1
Input turns to output turns
Ideal reflected torque
120 N·m
Input shaft
Keep the calculation and the acceptance figure on separate lines. The ideal result includes no approval margin, no shock and no verified effect of gearbox friction. The equipment designer needs the actual stationary load, the reverse torque path and the approved margin for the machine. A coupling that can open somewhere after the brake matters too. If it opens, the shaft at the pack can be held while the load side remains free. A higher brake rating will not close a coupling.
The quote may say “output torque” and mean torque at the output of the motor. The machine drawing may use the same words for the gearbox output. Write the name of the shaft next to each number rather than trying to reconcile those labels in an email. An assembly with the motor, brake and gearbox sold as a unit still needs a drawing that ties the advertised torque to the correct shaft and duty.
Why the holding column has no stopping energy in it
A brake holding a stopped shaft resists torque at zero speed. During a moving stop it has work to do. For a rotating inertia the stored energy is half the inertia times angular speed squared, so the same rotating mass at twice the speed carries four times the energy. On an incline, the load can add work while it descends. The stopping review therefore has to account for how long or how far the load travels under braking, and which component takes the work over that interval.
Put the holding and stopping cases on different rows of the order comparison. The first row needs a guaranteed or documented static rating for the exact option, with the conditions under which that rating applies. The other row needs the speed at application, allowable work per stop, the interval between stops, and any limits for temperature and wear. If a catalog lists an emergency stopping duty, look at its conditions before treating it as a production brake. If the machine circuit normally slows the drive and the pack applies at rest, state that sequence in the request.
Entry on a quote
Where it is used
Static holding torque
Load at the brake shaft after the drive has stopped
Dynamic torque, speed and energy
Any approved event in which the brake applies while moving
Duty or recovery interval
A sequence of stops and the thermal or wear conditions behind it
Motor starting torque
The drive's ability to move the load after full release
Brake release pressure
The chamber pressure conditions that open the friction pack
Make the fault condition explicit. “On loss of supply, the parking brake may apply while the shaft is moving” is a different requirement from “parking brake applied after the shaft reaches zero.” The equipment maker needs to resolve that difference in the fault analysis. A supplier can then answer the stated duty without extrapolating a stationary holding figure into a stopping capacity.
For the purchase record, write down which conditions the torque comparison leaves open. Examples include oil outside the permitted range, a drive that can disengage and a load applied from the opposite direction. Keep the open conditions with the drawing revision. That lets the reviewer see what was considered before treating the holding calculation as approval for the whole machine.
“Release pressure OK” needs a port and a time
That sentence on a service report can mean the reducing valve was set to the expected value, the branch gauge looked right, or somebody measured pressure at the brake when the shaft was already turning. The useful reading is at the release chamber and uses the reference specified for the pack. If the data sheet gives the pressure where release begins and the pressure for full release, record both as separate conditions. The first can explain why the shaft moves. The second is the one to check for drag.
Danfoss illustrates a further distinction on the TMK FL drawing. It gives full release at 15 bar difference between the drain/release and vent pressures, and a separate 30 bar maximum for the drain/brake line. The 1,050 N·m holding figure is given at zero release differential. Those values are for the cited TMK FL passive parking brake. The labels on the drawing matter as much as the numbers, since the maximum line pressure and the full-release differential are different checks. Use the corresponding sheet for the brake being quoted. Danfoss TMK FL technical information, printed pages 10–11
Consider a hypothetical quote for a different pack that needs 24 bar at its specified release port and allows up to 35 bar there. The branch gauge says 30 bar. A pressure trace at the brake shows 21 bar during the loaded start and 28 bar once the shaft is turning. I'd file 21 bar against the start and 28 bar against steady operation. That leaves a 3 bar shortfall at the moment the machine needs to release. A report that only carries the later number would miss it. This is a paper example, not a rating for a BLINCE or Danfoss part.
Now imagine the replacement needs only 22 bar to open but allows 28 bar maximum. A 30 bar peak at the release port would be too high for that example, even though the lower release threshold sounds easier to meet. Put the minimum and peak from the same port beside the limits on the new drawing. Where a shared branch drops pressure as another function moves, give the supplier the trace and the name of that function. The pressure at the branch inlet can stay useful in the diagnosis without taking the place of the reading at the brake.
Read the start trace from the shaft backward
Here is a hypothetical trace from a loaded start. The trace records a start command at time zero, first movement at 0.70 s and full brake release at 0.92 s. Those are three different events. The motor and brake data are in the service packet, so the analyst can match the movement to the brake manufacturer's stated condition for full release. In this example the shaft moved 0.22 s before that condition was recorded. A gauge reading taken after the first second would have missed the interval entirely.
Event in this hypothetical start
Time
What the entry records
Operator commands movement
0.00 s
Beginning of the trace
Shaft first turns
0.70 s
The first visible motion
Specified full-release pressure is reached at the brake
0.92 s
The first pressure evidence of full release
Pressure is steady at the brake
1.40 s
The later operating condition
The steady gauge misses a little over two tenths of a second. Look at the 0.70 s mark. There's movement on the speed trace, but the brake pressure hasn't reached its release line. I'd ask where the pressure tap was and whether the instrument could catch that interval. A gauge on the branch may not tell us what happened in the brake chamber. A threshold copied from another brake option can also move the line on the chart without any change in the machine. Both checks come before calling the friction pack damaged or ordering a higher-torque motor.
There is another trace I'd ask for if the loaded belt can start to run downhill. Say the brake is ready before the drive is. On the loaded incline, what is holding the belt in that interval? I'd want the drive evidence on the same trace before accepting the sequence. A valve command merely tells us when it was told to act. Put the motion and the pressure evidence on the same time axis, with the expected sequence from the machine drawing next to them.
For a stop, write the instant of last movement and the instant when holding begins. If the pack applies with the shaft turning, it is doing part of a moving stop. If the drive lets go of the load earlier than the pack takes it, look for movement between those events. Use the equipment maker's approved service method for observations under load. A stopped shaft can still be connected to stored pressure or a suspended load.
A creep complaint should also say which shaft moved. Put a mark on the drawing where the shop saw movement. “Drum moved a few degrees and stopped” and “input kept turning” send the reviewer to different parts of the drive. Give each observation its own location. Keep the brake pressure record and torque calculation with that sketch so the reviewer knows which shaft each one refers to.
Two drawings that fit the same flange can give different answers
Put the mounting faces on the same line. On one sketch the coupling starts just beyond the face. On the other, the shaft can reach the coupling but the drawing gives a shorter usable spline. Both can appear to fit from a photo. I'd take the distance from the face to the coupling on each drawing, then look at how much of the key or spline is inside the hub. A flange can sit flush while the hub has less usable engagement than it did on the old assembly. Where the motor and pack are separate parts, there is another joint to compare before the order goes out.
I'd leave the shaft load on a separate line. A sprocket hanging off the shaft and a drive carried through a supported coupling give the bearing a different job. The reviewer needs to know where the force acts as well as what shaft was selected. Give the supplier the layout showing that point. If the drawing only verifies the profile and length, the application can still have an open radial or axial load check.
The same comparison applies to the port sketch. Take the old release hose and follow it on the installed schematic. On one drawing it might end at a combined drain and release port. On another it may go straight to a separate chamber. Put the vent on the drawing too if the assembly uses one. Then compare the threaded connection and sealing form. A matching hose end tells me it can be screwed in. It doesn't tell me whether that point in the casting accepts brake pressure or carries leakage oil to the tank.
On the old and new drawings
Put beside the comparison
Mounting face and pilot
Drawing revision and the face used as the datum
Shaft and coupling
Projection and actual engagement after assembly
A and B, release, drain and vent where present
Port function from the installed circuit and thread and seal from the drawing
Brake pack
Exact option code and the conditions on its technical sheet
Load at the shaft
Force direction, application point and the applicable shaft limit
For a wet pack I'd also ask which oil it runs in. The BLINCE BMK6 orbital motor page lists an integrated wet multi-disc brake option. That gets the discussion to the right family. For an order, ask for the document covering the actual build. It should tell the reviewer how the pack is supplied with oil and which release, holding, fluid and temperature conditions apply. Put the machine's oil grade and temperature range on the inquiry. The option sheet has to do more work here than the product photo.
Draw the pilot line and the release line separately
On the downhill part of a cycle the conveyor can drive the motor. A load-control valve may meter the oil leaving the motor, according to the equipment design, while that motion is being controlled. The brake pack has its own job when the drive is parked. If the two devices are built close together, I'd still keep two lines on the circuit review. One line identifies what operates the load-control valve. The other identifies what reaches the brake piston.
A new release pressure can change the sequence without changing the mounting drawing at all. Imagine the new part fits and its static holding rating is adequate, but the old branch only supplies enough pressure for the previous release threshold. The order needs to go back to the circuit reviewer. Include the installed valve code and the actual brake option. Where the proposed fix involves a new setting or valve, the equipment maker needs to review the start, stop and fault response together before a change is approved.
What I would write in the request for a replacement
For the hypothetical conveyor, the purchase request can start like this. The brake sits on the gearbox input. The loaded belt pulls downhill at rest. The hydraulic circuit slows the belt during a normal stop, with the pack taking the load after motion stops. The reduction is 6:1. Our holding torque requirement on the worksheet is at the brake shaft. The port marked on the drawing is where the release trace was taken. For a different machine, change those entries to match the drawing and its fault review.
That gives a supplier something to check. An assembly code alone may tell them which family to quote, but it will not tell them what the brake has to do. The BLINCE BMR-BM01 hydraulic brake motor is a product reference for the request. Ask for the exact brake option, its rated holding condition, the release limits and a dimensioned drawing with the ports marked. If the equipment expects it to stop motion under a fault, add the fault and the conditions at application. Have the machine designer review any dynamic stopping claim before approving that duty.
When this is the second replacement, attach the record from the first. “Discs discolored at teardown” is something the shop saw. “Brake dragged during every start” needs a pressure and motion record. Keep those two lines distinct. Add the previous order code, service duration and changes made during installation. The supplier can then say whether the quote addresses a documented mismatch or whether the machine owner still needs to establish why the old pack failed.
If the quotation refers to a separate brake option sheet, ask for its revision with the order. A buyer reviewing the same assembly next year should be able to find the drawing, match the port letters and check that the pressure values refer to that exact option.
Leave the unanswered lines visible on the order
A buyer can get a correct answer to a fit question and still have no answer to a duty question. On the order, keep the items that were confirmed next to the ones that are still open. If a supplier says the mounting drawing matches but has yet to identify the brake option, leave the holding and release rows empty. If a supplier gives a static holding rating but the fault case applies the pack at speed, ask for the evidence that covers that event.
The same applies when a machine keeps moving after the command to stop. Record what turned. A drum that shifts through its clearance while the input remains still is one observation. A brake shaft that keeps turning is another. Have qualified personnel follow the equipment procedure and report which part moved and what pressure remained at release. Once that evidence is in the file, the next purchase can address a condition the machine actually showed.
Before approving the order, I would want the drawing to identify the brake shaft, the order code to identify the exact pack and the pressure record to identify its tap. The normal stop and the response to supply loss should have a named stopping component. Any condition still waiting on a manufacturer or machine owner should be written on the same page. That is the piece of paper purchasing can come back to if the equipment comes in again with the same complaint.
The time axis on a service plot may begin at the start command, while another begins at the first motion. Label the reference on each plot before putting them side by side. Where there is a separate vent on the brake, carry the two relevant pressure readings together. A release pressure difference calculated from traces at unrelated times is not evidence that the pack reached its full-release condition at first motion.
In a service review, keep the machine-specific pressure record beside the product rating. A brake port may have a different pressure at startup than it has after all functions have settled. If the trace only includes a steady value, note that limitation beside the approved release requirement rather than signing off the full start. Record which parts of the timing still need machine-side verification.
This article is a general engineering guide. Final component selection should be based on machine drawings, measured hydraulic data, working conditions, safety requirements, and confirmation from a qualified hydraulic engineer or supplier.
Blince Hydraulic Team
Blince Hydraulic is an industry-leading company dedicated to precision-engineered fluid power manufacturing and custom hydraulic solutions. Backed by decades of deep field expertise in industrial machinery and thousands of successful global deployments, our engineering team focuses entirely on high-performance hydraulic component manufacturing, including specialized orbital motors, high-pressure travel drives motor, and robust directional control valves. Our production infrastructure utilizes state-of-the-art multi-axis CNC machining systems and is fully ISO 9001 certified to guarantee repeatable volumetric accuracy across every single manufacturing run.
We deliver fast, highly dependable, and cost-efficient hydraulic solutions to heavy industry distributors, machinery OEMs, and maintenance crews across more than 150 countries. Whether your active project calls for a small-volume batch of customized shaft profiles or a large-scale production run of severe-duty cast iron gear pump, we configure our flexible production schedules to meet your target lead times with total pricing predictability. Partnering with Blince means securing maximum system efficiency, elite material quality, and uncompromised fluid power professionalism.
To learn more about our complete product lineup, visit our official website: www.blince.com.
