What causes these relays to chatter

The Aaon R88270 Heat Wheel Belt is a high-performance clear polyurethane belt engineered for seamless integration into Aaon energy recovery cassette (ERC) systems

York S1-024-18403-711 Motor

Can I use an aftermarket relay instead of the D6961607

Lennox X2669 Motor Assembly 322056-301 What causes these relays toThe Lennox X2669 Motor Assembly is an OEM HEPA motor replacement designed specifically for compatible Lennox Healthy Climate high efficiency particulate air filtration systems. This 120V blower motor is engineered to maintain the precise static pressure required to move air through dense HEPA media, ensuring optimal indoor air quality and system performance. As a direct fit HVAC blower assembly, the X2669 eliminates the need for field modifications,