Mixing-tank drive / Quote audit
Power, torque and rotational speed are related only at the same physical point and operating state. A motor nameplate rating, gearbox output speed and calculated agitator-shaft torque cannot be combined as if they were one measured record unless the ratio, efficiency, available torque curve, duty and mechanical limits are declared.
Prevent a false drive comparison
This page owns the quote-stage drive and load-basis audit. It does not select an impeller, predict mixing performance, approve a shaft or gearbox, define a hazardous-area design or replace the responsible equipment and drive suppliers' calculations.
Label electrical input, motor nameplate output, motor-shaft power and torque, gearbox input and output and agitator-shaft demand separately. Show ratio, direction, efficiency or loss assumptions and the exact speed beside any conversion.
Record the torque-speed-time profile for charging, acceleration, normal mixing, viscosity or solids transitions, upset recovery, stopping and restart. A short peak, breakaway event and continuous thermal requirement are different release fields.
Torque is not the only gearbox or shaft load. Preserve radial, axial and bending loads, mass moment of inertia, shaft length and support, impeller geometry and position, seal and mounting reactions, direction changes and critical mechanical checks.
Quote-to-quote audit
These rows expose the inputs needed for engineering review. They are not a gearbox selector, shaft calculation or promise that two nominally equal motors deliver the same mixing duty.
Swipe or scroll horizontally to review every evidence column.
| Audit row | Proposal A | Proposal B | Release record |
|---|---|---|---|
| Original ratings and physical points | Copy electrical supply, motor nameplate kW, rated motor speed and torque, drive/controller identity and the physical point represented by each field. | Copy the second proposal without converting or relabelling input, motor-shaft, gearbox-output or agitator-shaft values. | Original documents, units, revisions, value locations, included components and unresolved boundary differences. |
| Gear ratio, efficiency and output speed | Record motor speed range, exact gear ratio, stages, direction, stated efficiency or loss basis and minimum, normal and maximum output rpm. | Record the same fields independently; do not combine one proposal's motor power with the other's gearbox output speed. | Traceable motor-to-output calculation, supplier curve or table and every assumption or derating used. |
| Continuous torque and thermal duty | Show the required and available continuous torque across the operating speed range, duration, ventilation or cooling method and ambient or installation derating. | Use the same process load points and duration; disclose different motor, drive, cooling or thermal-limit assumptions. | Torque-speed curve, continuous current and thermal review, duty classification, margin policy and responsible approver. |
| Start, peak, cycle and upset recovery | Record breakaway and acceleration demand, peak torque and duration, starts or reversals, inertia, viscosity/solids transition and restart state. | Compare the same time sequence and product states; do not use an instantaneous maximum as a continuous rating. | Complete torque-speed-time load case, motor/drive overload envelope, gearbox limit and accepted recovery procedure. |
| Output-shaft and mounting loads | Record shaft and impeller geometry, overhung/radial, axial and bending loads, support and bearing arrangement, seal, mounting and direction of load. | Provide the second proposal's actual geometry and load calculation rather than importing a permitted torque from another mounting or shaft arrangement. | Configuration drawing, load reactions, gearbox/shaft/bearing checks, critical-speed or vibration review and unresolved interfaces. |
| Verification and change control | Define document review, no-load and loaded checks, current/speed/torque evidence, vibration and temperature observations and FAT/SAT acceptance. | Use the same acceptance questions and state any different instrument, calculated field, test material, duration or endpoint. | Evidence owner, approved configuration, exclusions, deviations, change triggers and production-release responsibility. |
Drive-release route
Start from the process demand and preserve every conversion and mechanical interface. The final drive is released as one configuration, not from a single formula cell.
Identify charging, startup, normal stages, rheology and solids transitions, upset recovery, stop and restart with speed, duration and observed or calculated torque demand.
Record motor, VFD or starter, coupling, gearbox, ratio, output arrangement, shaft, bearings, mounting, seal and impeller revision.
Keep every value at one declared point, show the calculation or supplier curve and compare required versus available continuous and transient duty across the full speed range.
Add radial, axial and bending loads, inertia, critical-speed or vibration questions, thermal conditions, lubrication, access, guarding and maintenance interfaces.
Assign document, FAT, SAT and production checks and state which material, geometry, speed, duty or component changes reopen the engineering review.
Agitator drive RFQ checklist
Unknown values remain open for the responsible equipment, drive and site reviewers. This checklist does not calculate a safe motor, gearbox, shaft or operating point.
Open the process briefMaterial/formulation and lot, batch quantities and fill levels, viscosity/rheology and solids by stage, addition sequence, temperature, settled or restart state, primary duty and endpoint.
Minimum, normal and maximum agitator rpm, ramp, holds, cycle duration, starts, stops, reversals, upset recovery, duty hours and measurement or setpoint basis.
Continuous, start/breakaway, acceleration, peak and upset torque by speed and duration; calculation or trial basis, inertia and responsible process reviewer.
Motor rating and rated speed/torque, supply, pole and duty data, VFD or starter, control mode, torque/current limits, low-speed cooling, overload duration, protection and derating basis.
Type, ratio, stages, efficiency/loss basis, rated and maximum output torque by speed, service or application factor method, thermal rating, mounting, lubrication, coupling and rotation direction.
Shaft diameter/length/support and material evidence; impeller type, diameter, count and position; vessel dimensions, working levels, baffles/internals and clearance drawing.
Radial/overhung, axial and bending loads; bearing and mounting reactions, seal load, critical-speed/vibration review, guarding, access, removal, environmental and hazardous-area responsibilities.
Calculations and curves, data sheets and revisions, no-load/loaded test plan, current/speed/torque measurement basis, temperature/vibration evidence, FAT/SAT criteria, approvers, exclusions and change triggers.
Draft source record / Pending technical review
ABB and SEW-EURODRIVE establish the general drive relationship and project-planning fields. The current ITT Flow Technologies / LIGHTNIN product page provides a named mixer example in which power, speed, gearbox and output-shaft scope remain tied together. Their margins, products, values and performance statements are not transferred.
Buyer decision FAQ
At the same rotating shaft and operating state, P = Tω. With mechanical power P in kW and speed n in rpm at that same point, T in N·m is approximately 9550 × P ÷ n only for n > 0. Do not use the divided form to calculate zero-speed breakaway or stall torque, and do not mix motor input or nameplate power with gearbox-output rpm unless the complete drive conversion is documented.
For n > 0, the rearranged equation gives higher torque at lower speed only when the same mechanical power is actually available at the same point. It is undefined at zero speed and cannot establish breakaway or stall torque. Motor and VFD loadability, gearbox ratio, efficiency and limits, thermal conditions and the real process load can prevent the lower-speed assumption from being true.
Not as a release value. Nameplate rating belongs to the motor. Record rated motor speed and torque, drive-control range, gearbox ratio and losses, output torque limits, coupling and the complete load case before calculating or accepting agitator-shaft availability.
No universal factor is published here. The source and definition of any service or application factor must be declared beside the actual continuous, start, peak, cyclic, reversal and upset load case, mounting and shaft reactions, then confirmed by the responsible suppliers.
An agitator shaft and impeller can create overhung, axial and bending loads that act through bearings, gearbox, mounting and vessel structure. A permitted output torque alone does not release those loads, critical-speed behavior, sealing or the mechanical arrangement.
Include material and batch load states; required speed, continuous/start/peak torque and duration; motor and control data; gearbox ratio and output limits; shaft, impeller, vessel and mounting geometry; radial/axial/bending loads; environment and safeguards; calculations, tests, approvers, exclusions and change triggers.