I have an electric furnace 240V. The blower motor starts then slows and sounds like it is laboring after about one second. It does start at full speed, however. Does the same thing when in constant on setting. There is a solid state time delay relay (on delay is 1 second off delay is 45), a blower relay, transformer but no control or logic board. I've verified 240VAC on load side of breaker. I've tested the elements and sequencer and they test normal. and I'm assuming the blower is ok as it starts at full speed then slows and it sounds labored while continuing to spin. Cycling power has no effect - starts full speed then slows. The timer relay is 24VAC. I'm unfamiliar with the characteristics so not sure what I'm looking for. I've narrowed it down, I think, to the timer relay, blower relay or, less likely, the transformer.
Any help would be appreciated.