Marathon Motor Cross Reference

Marathon Motor Cross Reference - WorldWide Electric & NAE Equivalents

Marathon (Regal Rexnord) shows up on everything from HVAC air handlers to inverter-fed process drives - the Blue Max line practically defined inverter duty. Crossing Marathon to stock follows the same NEMA five-point match, with a couple of line-specific notes below.

The Five-Point Cross

Check From the Old Nameplate Must Match?
HP & RPM Rated power and full-load speed Yes - same HP (or one up), same pole count
Frame NEMA frame number (e.g. 184T, 326T) Yes - frame match = bolt-in fit
Voltage / Phase e.g. 230/460V, 3φ, 60 Hz Yes
Enclosure ODP, TEFC, TEXP, washdown Yes, or upgrade
Service Factor & Design SF 1.15, NEMA Design B typical Equal or better

Because both brands build to NEMA MG-1, a frame match guarantees the mounting dimensions - details in our frame size chart and nameplate guide.

Where Marathon Lines Typically Cross

Marathon Line Duty Our Equivalent Series
XRI® premium efficient General purpose TEFC PE / PEWWE Premium Efficient
Blue Max® inverter duty VFD / vector drives PE inverter-duty TEFC · TENV
Blue Chip® severe duty Harsh industrial Severe Duty Cast Iron
Washdown / SST Food plants Washdown Stainless
Fire pump / special duty Per listing Call - listed-service motors are matched case-by-case
General purpose & HVAC Fans, blowers, pumps Integral TEFC · ODP

Marathon Cross Notes

Blue Max motors are often applied at wide constant-torque turndown (some rated 1000:1 with vector drives and separate blowers). Match the application's real turndown need, not just the motor label: standard inverter-duty PE motors handle typical 10:1 constant torque; below that, spec TENV or blower-cooled and confirm with your drive parameters - our VFD guide covers the checks.

Marathon model numbers on the nameplate (e.g. 5K49MN4...) matter less than the spec grid. For fire pump, hazardous location, or definite-purpose listed motors, cross only to equivalently listed units - send the full nameplate.

Frequently Asked Questions

What replaces a Marathon Blue Max on a VFD?

An inverter-duty premium efficient motor with MG-1 Part 31 insulation matching HP, RPM, frame, and voltage - plus a cooling check: if the application runs extended low-speed constant torque, step to TENV or blower-cooled designs to preserve the turndown range.

Are Marathon XRI and NEMA Premium the same thing?

XRI is Marathon's premium efficient branding; it meets NEMA Premium levels, as do our PE and PEWWE lines. Compare nameplate nominal efficiency for the exact rating - differences are typically fractions of a point.

Can I cross a Marathon HVAC motor by the OEM number on the fan?

Use the motor nameplate, not the air handler's parts list - OEM numbers frequently map to standard NEMA motors with a specific mounting (resilient base, belly-band, C-face). Photos of nameplate plus mounting get an accurate cross.

Do you handle Marathon vertical pump motor crosses?

Yes - vertical hollow shaft and P-base motors cross on HP, RPM, frame/base diameter, and thrust rating. Thrust is the critical extra spec; it's on the pump datasheet if not the motor nameplate.

Marathon lists 208-230/460V - my plant is 208V. Does the cross need that?

If you run 208V, match a motor rated for it (208-230/460 or 200V). A 230/460-only winding on 208V runs hot and loses torque margin - this is the most common voltage mistake in HVAC replacements.

Related Resources

Send the Marathon nameplate - we'll return the cross and price.

Most in-stock items ship same-day; call to confirm availability and freight.

Call (888) 203-2358

All manufacturer names, brand names, and part numbers are trademarks of their respective owners and are used for identification and compatibility reference only. Texas Belting & Supply is not affiliated with these manufacturers. Replacement suitability should be confirmed against the original nameplate - call (888) 203-2358 and we will verify the cross before you order.