57 Stepper Motor 57BYGH56 3A 1.26 N·m High Torque (8 mm shaft, no cable)

Stepper motors · 1 option in stock

Stepper motors — frame size, step angle and torque are the three decisions. The parameters are listed in order of importance: the one at the top decides the most, and no amount of care further down makes up for getting it wrong.

This page lists 1 option, from ¥80.

What this part is

57BYGH56 stepper, NEMA23 flange (57 mm), 56 mm body, 3 A phase current, 1.26 N·m holding torque, 8 mm shaft. The usual motive power for engravers, CNC and the Z axis of a large 3D printer.

The parts of this item

Figure 1 — A motor needs five numbers: frame size, body length, shaft diameter, shaft length, lead count — frame size is the mounting size

The parameters that matter

Not every number on a part like this is worth the same. These are the ones that decide whether it fits and works, and what to look at for each.

How to choose, step by step

1. Torque — Work it out from the load, do not guess. Torque falls as speed rises, and the catalogue figure is at low speed — leave margin at the top end.

Reading the part numbers

You can order by part number or by selecting the parameters. The part number is fastest, but it does not always encode every parameter — the selector on this page is the authority.

8 common mistakes

1. Frame sizes do not adapt. NEMA 17 is 31 mm between holes, NEMA 23 is 47 mm. There is no bracket that fixes getting this wrong.
2. More torque is not better. A big motor has more inertia and accelerates more slowly; on a light mechanism it shakes. 1.5–2x your calculated load is the right margin.
3. Set the driver current. Match the motor rating. Too low and it stalls, too high and it cooks.
4. Torque collapses at speed. A 42 mm motor on 24 V loses most of its torque above about 600 rpm. For real speed, go to 48 V or closed loop.
5. Never unplug a motor live. Disconnecting the phases while the driver is energised destroys the driver.
6. Resonance is a real failure mode. A damper or a mid-band change in microstepping fixes a motor that howls at one speed.
7. Measure before you order. Take the old part off and measure it, or send us a photo with the caliper reading — that beats guessing from a model number every time.
8. Everything here is in millimetres. Where a size is imperial, convert it: 1" = 25.4 mm, 1/4" = 6.35 mm, 3/32" = 2.38 mm.

Telling it apart from lookalikes

Against a 57BYGH76 (long body): the 76 has more torque (about 1.8–2.2 N·m) but more inertia and slower acceleration. The 56 is short, light and quick, right for moderate loads.

Confirming it is the right part

This page has one configuration, so there is nothing to choose — which makes confirming that it is the right part more important than studying the specification. Three steps is enough:

1. Measure the mating dimension — the one place this part touches something else: bore, shaft, thread, tube OD, or hex across flats. It is the number people get wrong, and half a millimetre out means it will not fit.
2. Measure the outline and the mounting hole spacing. Two parts that do the same job from two makers often differ by 2–3 mm between holes: it looks like it will fit, and it goes on crooked.
3. Send us two photographs: one general view showing the machine and where the part sits, and one close-up with the caliper reading in shot. If the machine has a nameplate, include it — plenty of these parts are specific to one machine, and the model number locates them faster than dimensions do.

When to replace it

You do not replace this until it fails — but "still looks usable" and "still reliable" are two different things. Any one of these and it is time:

• Lost steps at low speed with the driver current correct — usually a weakened magnet or a worn bearing.
• Hot at no load, or a regular noise once per revolution.
• Radial play at the shaft, so the coupling cannot drive it cleanly.

Fitting and use

Before wiring

• Confirm voltage and polarity first. Reversed, it is destroyed on the first switch-on — there is no second chance. DC parts especially.
• Wire with the power off, then check continuity and insulation with a meter before you apply power.
• Crimp or tin the wire ends. Twisting bare strands onto a terminal gives a high-resistance joint that heats up.

Mounting

• Leave the heated parts some air. Do not mount them against plastic or against the cable run.
• Parts with a direction (fans, check valves) have an arrow. Reversed, you lose most of the airflow or flow.
• Fasten it properly. Vibration loosens terminals, and loose terminals are the most common electrical failure there is.

First power-up

• First power-up from a current-limited supply, or through a fuse. If something is wrong the damage stays small.
• Run it unloaded first, measure current and temperature, then add load.
• After 30 minutes feel the terminals and the cable. Anything noticeably warm means high contact resistance — re-crimp it.

Three things not to do

• Do not connect or disconnect under power unless it is explicitly rated for hot-plug. The arc damages the terminals.
• Do not run above the rating. It works for a while, then it does not.
• Do not skip the earth or the fuse. You save a few yuan and risk the machine.

Matching parts

• Driver — current has to match
• Coupling — check the shaft diameter
• Damper mount — cuts resonance noise

Lead time, custom work and shipping

• Stock sizes: dispatched in 1–2 working days, subject to stock
• Custom: non-standard sizes, materials and treatments are possible — send quantity and drawing
• Shipping: from Shenzhen; domestic courier by default, DHL or dedicated line for export
• Volume: quantity pricing available, contact us for a quote

If you cannot find the size you need, or you are not sure which one fits, send us the problem you are solving — what machine it goes on, the dimensions of the part you have, what it has to achieve — and we will match it.